Their house. Their rules. Leave your pistol in your car. If they insist on making an issue of the fact that you own guns, well, I am not trying to be an SOB when I say this, but a man's got to stand on his own two feet. Explain to them that whenever they want to open civilized communications with you, they'll have your number. Then walk away.
My mother is an anti-gun, liberal hippy type who forbade me from owning guns or even being around them, to the point that she would not let me go to Boy Scout camp if there were going to be any guns, and not go to Scout summer camp unless the Scoutmaster promised I wouldn't be allowed to shoot at the rifle range. She also filled me up with a lot of pap about how one should not only turn the other cheek when faced with violence, but that it was morally and intellectually superior to let my self be beaten to a pulp than to raise a hand against another human being. That made me a lot of fun on the schoolyard, let me tell you- I got beaten up regularly because I would never fight back.
Suffice it to say that has all been finally purged from my system some time ago. There's a difference between instigating violence and protecting oneself.
I learned to shoot from Scouts, so I guess she was right about the Boy Scouts corrupting me with guns. I bought my first gun the day I turned 21 and had to keep it at my Dad's apartment because Mom wouldn't let it in the house, and threw a hissyfit when I told her what I'd bought that day. Strained things around the house let me tell you. I never kept guns in the house while I lived there to respect her rules, but I didn't live there much after that.
I still hear from her every now and then. It's a shame that my kids don't know their grandma very well, but she brought it on herself.
