I have a good friend like this. He says quite extreme things like that from time to time. I don't attack him for it. Instead we talk about it. I ask him questions, share my view on the matter etc. more often than not he then walks back what he said and openly admits that he shouldn't generalize and understands that the few bad apples he has had to deal with don't represent the majority.

People change. I did too. I used to say horrible things about gay people myself too when I was younger. Then I grew up and realized I'd actually like to have some of that dick too.

Your friend on the other hand probably only holds down to those beliefs even stronger now because of how you reacted. These are the people who vote for Trump to "screw with the libs"