Doesn't bother me. I just don't respond. I've shown pictures (online) of exactly two guns that I own. One is a Garand and the other is a highly engraved S&W. Both times the audience was one that I felt would appreciate that particular firearm.
I don't collect guns, I acquire them. None of mine are really collectible and I only keep them to shoot. I'm not much of a show-off so why would I take the time to take and post pictures of nothing-special shooting irons just to satisfy someone else's desire for gun ****?
As to the larger issue... I'm generally evasive when a relative or acquaintance asks how many I own. I say something about guns being nothing more than tools where each one has a specific purpose. If I'm pressed about it, I'll explain that the majority of my collection are heirlooms that have sentimental value only and aren't very good for target shooting or hunting. Then I have my basic hunting guns and a set for my son. Throw in a few handguns and it seems like an arsenal, which it really isn't. It's barely a respectable collection and none of anyone's business.
To a much greater extent than most mechanical devices, firearms are terribly unforgiving of any overconfidence, complacency or negligence.