Read the comment below from Barbara.
It is very simple, you are free to say that -let's say- black people and inferior people. Totally free in my eyes to say that. You'd be an idiot, but freedom allows you to be an idiot.
What you can't do is enforce your beliefs, because that is the actual discrimination.
The laws are there to protect minorities, not from vile speech, but from actual harm. However, even discrimination laws have their limits. Especially regarding to gender, because there *are* actual physical difference between men and women (feminists will never allow this to be true, but it's pretty much scientific fact). So, I can understand that an employer wouldn't hire a female truck driver, because in the event of a flat tire, she wouldn't be able to help herself because changing the tire would be too heavy. Of course, this would depend on the candidate. I know very physically strong women, but that is not how feminists think. That said, they're not battling for women to become truck drivers, but for women to get so called white collar jobs in management.
So, no, discrimination is not equal to political correctness. I am not politically correct, because I'm not afraid to say what I think even if it is contrary to popular beliefs, but I do not discriminate (at least, I try not to... it is apparently impossible not to discriminate at all)