Not long ago, we had one of my BIL's friends come by for dinner while he was visiting. I wouldn't have minded so much of her political rantings except that she was mostly talking TO MY CHILDREN. I deflected as often as I could- you don't "WIN" these things - and once the kids were finished, we left so they could have their Trump hate fest.
THIS was the kind of thing I don't like - rude, argumentative types. Had I known she was going to be this way, I would have asked my guest to not bring her for DINNER - just come by if she liked.
People who can't keep their political mouths shut are not welcome at my table. Ditto religion or any other social issue you need to vent on - I have vegan relatives who have to "inform" me - it's not just politics. If you come to my house to argue, you can stand outside and shout at the wind. Life is just too damned short.
Wait, she did this as a guest in your home?? And you didn't kick her out?
Is it just me? The second she started I'd have told her to STFU. If she refused I'd have physically escorted her out. And PS take the BIL with her because he knew what she was like and inflicted her on you anyway.