Number one your teacher is obviously ignorant as fuck.
You should have asked him why the fuck white people were too lazy to build this country on their own. I would have challenged the fuck out of him right in class.
The very fact that he even let those words come out of his mouth shows that slavery isn’t a big deal to him. Oppression doesn’t matter in his eyes. His privilege as a white male blinds him from understanding the deep rooted ills of oppression.
I think that there shouldn’t be a “next time” because you should tell your principal and if he/she doesn’t see a problem with a teacher who believes slavery wasn’t racist then you need to go to some higher ups. Group up with students who agree with you. Start a petition, go to the news, get people to hear about it. There is no reason someone who is ignorant enough to not only believe but teach students that the biggest form of oppression in the history of the world wasn’t racist shouldn’t be teaching. He doesn’t deserve his job.
He isn’t worthy of milking the brains of the youth.