It's because in America, they have freedom of speech. We, in the UK, have freedom of speech but with certain restrictions, which has lead our country to becoming more careful of what we say. Americans are allowed to be homophobic, racist and generally are allowed to speak out more so that's why there's that contrast.
This is why Austin, Farrah and Jenna are so loud. They are not obnoxious, they are
American. That's how they are, always outspoken and honest and never holding back like us Brits.
just in case you wanted to know