Thanks for all the replies. I posted because I'm wondering about whether my current thinking makes sense. It's by default, not intent, that our house currently has no toy guns. The issue just came up when the kid was mulling his Halloween costume options. He proposed a Star Wars character with a blaster, but ended up choosing to go as an unarmed (not one-armed) pirate, probably because he's never seen a pirate movie with black-powder firearms or whatever was the carry back in that day. So the issue was deferred, but not resolved.
To be sure, I could see myself letting the kid play with toy power tools without my fretting to an online forum about whether he would take the sawzall to the cat or something. So that's a possible contradiction. And yes, the kid plays with imaginary guns, so whether he has a toy one or not may be irrelevant.
That said, we skipped getting the kid a tricycle or bicycle with training wheels -- both legitimate and fun toys -- because both provide the wrong kind of training for someone looking to ultimately ride a two-wheel pedal bike. Instead, we went straight to two-wheels (without pedals) and the kid was riding a real bike at a very early age.
I suspect this may be the real reason for my current aversion to toy guns. I basically can't wait to introduce him to the real thing and wonder whether he'll just be happy with toys for longer than I'd like. Or learn hard to break habits. But he's a kid and kids play, so...
I also suspect--actually realize--that times have changed. I recall going to summer camp as a kid where you could check out a .22 rifle as easily as a canoe. I'm pretty sure a kid taking even a toy gun to camp or school nowadays would run into some politically charged problems.