Can someone explain the concept of whiteness in America?

There's this whole thing happening on Twitch.tv where a creator called someone "cracker" and then he got banned with people calling him racist towards white people. I'm European,this whole thing sounds ridiculous to me and i didn't even know that term exists,but i saw a lot of comments some serious,most of them joking,asking about who is white enough and has the "pass" to say that word. I know Americans don't consider Latino's white even if the majority of them are white skinned,then there's the Jews,white Africans,but the craziest part is that i've seen some say that Italians aren't white either.

From what i understand,they generally view white people as the colonizers and exclude minorities of white people that suffered as much as black slaves. I'm Greek,my people were slaves to the Turks even longer than black people in America,am i white in the eyes of Americans? What about Poles or Armenians?

/r/AskReddit Thread