Okay...I want to make sure I'm understanding you. If a very nice police officer lived next door to you and owned guns - you would not be friends with him for that reason??
I'm not going to be hostile, but I'm not encouraging a friendship.
I would be polite and pleasant when I saw her or him outside. Beyond that, no, I would not want to be any friendlier, and I certainly would never set foot in his or her house, nor would I want them in my home. My children would not be allowed on their property ever.
Actually, I have a neighbor who is a cop. The guy is a horse's patoot, so the point is moot. But I do wave and say hello, but no, we aren't friends.