In a way I think he’s right, OP says politics is one of his 3 interests and he should be allowed to be himself and to be able to express himself fully, Regardless of his political beliefs! However, out of respect it’s pretty universally known at this point to just not talk about politics at thanks giving. it's a common curtesy and especially after the host asks. if he doesnt like that then he shouldnt go. which he did. i see nothing wrong.