Oh, you're pathetic. I'm not passing judgement on swinging but the fact that Mom may have advertised that the door is open ... and "you're welcome in" (at midnight). I'd feel the same way if Brenda was a nun. I couldn't care less if they swing ... although I would submit it is better done BEFORE having children or AFTER they leave the home.
You will certainly not agree ... but most people who swing may be be well adjusted sexually but there is a higher probability that they are not. Who needs these people opening doors in the middle of the night?
But then, there's no explaining your POV.
She has a too quick trigger finger for bashing Christians. She obviously thought you were saying it was her lifestyle that caused the problem. Not the potential that her meeting with the neighbor could have gaven him an implied or an express invitation to their home.