I have lights on maybe 3 pistols at any given time. If I'm shooting a class with one of them, I don't take it off on the grounds that that's ####ing stupid. If I was at a class and somebody was like "uh, there's no low light component, duh" I would not do or say anything cutting in response, because being that stupid is punishment enough. Lots of WML holsters use the light for retention, so what, now I'm supposed to have two holsters, just so some moron doesn't have to make his brain do a single pushup?
Bit of weight on the muzzle can soak up some recoil, not that it makes a big difference to me on most service guns I can think of, but it's still an advantage.
I like having lights on handguns because I like having the option of lighting up a target without removing a hand from the gun, or one-handed while doing something like dialing 911, or holding a kid, or hanging onto a dog, or checking a pulse, or doing a very simple juggling routine.
You want a light on your gun? Get a light on your gun, and ignore people who want you to fit their clearly ill-informed gun fashion sense.