Because "how much profit is excessive? isn't a simple question but a facile one. Profits are considered excessive because of the distribution and conditions precipitating it. Not any absolute quantity of ...what? The question makes no sense.
This, actually, is symptomatic of something that annoys me greatly about many recent discussions, and it is the lack of specificity. And this lack is so pervasive that it can't be coincidental.
People say they advocate a living wage. I say "how much?" I don't get an answer, because my question is considered "complex." People say corporate profits are too high and there should be a limit. I say "how much?" I don't get answer for the same reason. I'm willing to discuss any given number for either of those questions. I'll probably be on the opposing side of the discussion, but I'm willing to discuss it. I'll be reasonable and discuss it.
But I'm not given an answer to be reasonable with. Sure I'll probably disagree and I'll be considered unreasonable, but I'm being reasonable enough to actually talk about the number. But I'm not given that. I'm given floating abstract targets that nobody knows what they are.
It's not MY job to come up with the specific problem. If a person says "here I have identified what I think to be a societal problem and something should be done about it" it is the job of that person, not me, to say "and here is the what should be done about it."