One of the things that you need to know if you want to live in the US is how to be politically correct. That means you suddenly become aware that people around you are different.You should learn to accept these differences. Sounds nice?
The fact is that everybody is somehow different. Groups of people that have something in common, so they are different in the same way, expect you to learn how they are different and act as if you don’t mind. You’re not allowed to say anything remotely close related to the difference. Now imagine all the ways people can be different. Remember, not remotely close!
Freedom of speech? I don’t think so. Look at the bright side: you have freedom of thought. :)
How did this happen?
Given the fact that common sense is an abstract term there needs to be something to tell people to do the right thing. Every time. Yes, even when they don’t want to.
So how is this enforced?
When you feel offended by something someone did or said you seek ‘justice’. You simply sue that person. And chances are you will win.
What to do?
Learn to keep your mouth shut. Weather is a safe subject.