Reason requires time, effort, and very deliberate cognitive processing, and thus motivation to bother engaging in it. By definition, apathetic voters lack such interest and motivation. Thus, they are more likely to take the easiest route to a decision, which is always emotional reactivity and the highly biased and error prone outputs of automatic forms of information processing. They are not the only emotional voters. Plenty if not most highly interested voters vote via emotion and biased thinking, but interest and motivation are neccessary prerequisites to even begin to form and informed and reasoned opinion. Thus, adding apathetic voters can only increase the % of voters that are uninformed and/or don't care enough to apply reason to the information they have, and thus will make either random or emotional choices.
We could be getting hung up on words. I took your original statement about "apathetic voters" to be about
people who are apathetic about voting. You seem to be using it to mean
people who vote, who are apathetic about everything. Obviously if someone has no motivation whatsoever, they aren't helping matters by voting. But it's easy to imagine people who are extremely motivated to learn the facts and reasons behind our political system, and having done so, conclude that their voting is not a strategy likely to bring about meaningful change.
No, I am
not referring to people who don't care about anything. I am referring just to people who don't care enough about the impact of their voting to vote. Becoming informed and then applying that knowledge at the time of voting don't just happen naturally, it takes immense effort and vigilance that requires a strong source of motivation. Non-voters fall into 4 general categories, only one of which are the group you refer to. First, there are the people who don't know whether there is any impact, they just don't want to bother voting. Given that the immense effort to get informed and apply that knowledge to voting is largely motivated by the same desire to have a impact that would motivate voting itself, there is zero motive for these non-voters to have become informed in the first place or apply that knowledge if you coerce them to vote. The second group are people who believe there is an impact, but just don't care about having that impact, just like I believe in the impact of exercise but don't care enough to actually do it. Just like the first group, they have no motive to put forth the effort to become informed or apply that info to voting. Third, there are the people that based mostly on ideology and unreasoned pessimism believe their is no impact of voting, so they don't bother. Since their belief in the non-impact of voting is not itself informed, their resulting non-voting cannot be informed. Finally, there are your noble abstainers who made an effort to inform themselves apply it to the options, then decided their was no impact so they don't vote. But, once they decide their is no impact, what is their motive to stay informed and apply that knowledge each election to decide if any realities have changed that make a vote impactful? I'd argue none, thus most of them become uninformed and unreasoned non-voters once they have reached that decision that voting has no impact. I'd also argue that it is objectively so implausible that voting is equally non-impactful for all sorts of elections and across time that any person that consistently does not vote cannot plausibly be basing this in an informed assessment of the impact and instead is blindly applying a view that has become a dogma.
In sum, the people that become and stay informed and continually are willing to apply their knowledge to their decision on whether to vote are a tiny fraction of non-voters who are also the most likely to vote under some circumstances because impact objectively varies and they are supposedly informed enough to notice that and motivated enough to act on it.
I'm apathetic about voting because I know that our electoral system is highly inefficient and easily corrupted by monied interests. If I got all my talking points from AM radio comedians, maybe that information wouldn't prevent me from caring enough to vote in a Presidential election. But knowing what I know about campaigns and how they're financed, and how meaningless my contributions are on a first-past-the-post ballot, I have become apathetic about voting due to my understanding of these matters. Emotional appeals have no effect on compelling me to vote for President; in fact, literally the only thing that would make me do it is the possibility that my home state will not vote ~80% Democrat as it always has. So, to your original point, the time, effort, and cognitive processing that I devote to educating myself about American politics is why I can't be bothered to devote any time or effort to voting for President, except under very narrow circumstances.
I don't doubt you are in that tiny % of non-voters that care about the outcomes of elections but believe that you don't have an impact. However, note that you confirm my argument that this small subgroup would vote sometimes depending upon the variable impact. You don't vote presidential because you're area already goes Dem every time, but you would vote if you thought it might not. That means you are already making a decision on how you would vote, you just are not actually voting when your informed views says that the way you would vote wouldn't impact the outcome. Thus, when you don't vote there is no benefit to you actually voting, thus no benefit to coercing you to vote. In contrast, coercing all those other sub-groups of non-voters to vote would be harmful in general and even to themselves since their non-voting is tied to the same lack of motivation that would make them uninformed and subject to emotional routes to decisions that require the least effort.
Finally, I would argue that it is objectively implausible that the choice options have absolutely zero impact, despite systemic corruption and common tethering of both parties to monied and corporate interests. Thus, an informed person would only not vote if they lack sufficient concern for what differences do exist. For example, both parties are far from my ideal and corporate influence greatly concerns me. But I vote because I still recognize objective impactful differences, such as Supreme Court appointments, that are created by the objective differences between the parties that do exist, such as the type of citizens that each tries to appeal to when increasing turn-out, with republicans appealing to racist theocrats. That real difference is something I care about enough to vote on.
Now, maybe some informed non-voters do have some concern about the differences, but just greater concern for systemic corruption, so they don't vote as a form of protest to hope to change the system. That can be informed, so long as the person acknowledges the real differences between the Dems and Repubs and that their decision may harm their own interests in the short term in the hope that their "protest" vote will have long term benefits. But any non-voter that simply claims no differences between the parties is so objectively wrong that they cannot be an informed voter (not saying you are among them, because that isn't an argument you made, just one many "protest" non-voters do make). In my experience, denial of those significant differences is usually rooted in arguments fueled by an ideology of convenient cynicism or a desire to highlight particular problems (like corporate influence), even if requires taking unreasonable stances like claiming both parties are identical.