When I was very much younger and for a few years married to man with a very rude father who repeatedly insulted me and showed he had contempt for any views I held on almost any subject - I decided not to react and carried on saying what I thought and acting they way I always did. He escalated, I acted as if he was being perfectly amicable and ignored words like ridiculous, stupid etc so he further escalated and still didn't manage to get the response he was obviously after. As he did this in public, particularly in front of people we knew, he was the one who looked foolish, I just appeared tolerant. Years later, after the husband was long gone, acquaintances still comment on how vile his father was. I was well shot of the pair of them to be honest but pleased I always kept my cool and good manners. Since then there have been situations where I have called people out for bad behaviour but generally I prefer to ignore it as it's their problem and I don't need to make it mine.