There's not much point in arguing about whether the cop was justified in this context. Your general point it true either way. Had he not been brandishing a toy gun he would not be dead.
My point is more that the same can be said of most any accidental death. Had he not been on that swing set he would not be dead. Had he not drank a quart of Jack Daniels and gone into that swimming pool he would not be dead.
But when I hear someone drank a quart of Jack Daniels and drowned in a swimming pool I am not moved to call for the banning of either Jack Daniels or swimming pools.
We aren't TALKING about people here though. We are talking about kids, who cannot understand the gravity and danger of their actions.
We are talking about things that look like weapons. That even if seen clearly and in good light a cop would actually be MORE sure he needed to defend himself.
You must really suck at Bayesian analysis and heuristics if you can't understand that just because some cops mistake things that are not clearly weapons does not abrogate the need to prevent the proliferation of things that ARE clearly weapons in the hands of kids (particularly when despite the clarity of their weapon-ness they are not weapons).
Just because the dice come up winner once for you, it does not mean that it is a good gamble to have taken. And just because they come up loser does not mean it wasn't. It is based on the odds. And the gamble you propose increases the odds of dead children, and doesn't improve any measurable payout. It is flatly a bad gamble, and those kids represent my money and survival potential. You are gambling with my money and life when you gamble with kids, and for what? Amusement? Do you LIKE seeing more kids shot because they have targets put on them?