Juls,
I do understand. I´ve been in that situation many times. I also don´t like it when people just talk and talk and usually they don´t take subtle hints. Usually it´s the other way around for me and it´s my esthetician or my massage person who just talk non-stop. I usually tell them I´m so sleepy I cannot talk and then I yawn. I tried to tell them before I just wanted to relax, but that made them angry.
About reference to people´s race or politics, that is just very difficult. I can usually never keep my mouth shut and it always results in a fight. When I tell them I don´t like to hear comments like that, they get very defensive. So I believe the best course of action is to say: "Well! Right!" And then dismiss it.
Or say nothing and just let the words hang out there for a while, then change the subject. I think direct comments just makes these people more aggressive.
In any case, you have my sympathy.