They're called self-loathing Americans. They hate any idea of American exceptionalism and try and define America First as racist. I believe a lot of it stems from the elite university campuses. America isn't, or hasn't been, perfect, but its pretty damn good.
I'm not a big "rah rah" red, white and blue guy, but I'm thankful that I live in the US with its freedoms, particularly freedom of speech, which includes those that aren't proud of America. I also believe dissent is healthy. However, name calling, threats and vandalism aren't dissent or debate, its just immaturity and stupidity. (guilty myself sometimes on the name calling).
I have an American flag on my house and mailbox. That's how I show respect and pride for my country.