Why are Americans like that with Hispanics?

Many Americans hate Hispanics for the same reason many Hispanics hate Americans, and for the same reasons many people hate other people. Lack of understanding, lack of knowledge, lack of communication. Thankfully, many of us just get along. I wouldn't let it bother you. The more you travel, the more you realize people are the same everywhere. All cultures have prejudice against another in some way and while it is unpleasant, being bothered by it is letting them win. Be the better person and educate them politely.