Yeah, I've had to deal with someone saying that he could cuss people out without fear of reprisal because of the freedom of speech. No. The government telling you they can't arrest you for it is not the same thing as being a jerk and people not wanting to associate with you anymore.
We're legally allowed to do lots of things that are considered impolite. No one will arrest you for being 2 hours late to a party, but it's still incredibly rude. The same applies here.
If he was an American, I'd have started talking about the first amendment right to freedom of assembly (that's also vis-a-vis the government, but he may not realize that).
With regard to the original, yes they have the right to say offensive things. They don't have the right not to be told that it's offensive, and "I will not associate with people who use that kind of language" is also free speech.
At most, the laws may give me the right to cuss someone out and still bring charges if they respond with physical force. It doesn't mean they don't get to cuss me out in return. My freedom of speech includes the right to post on Facebook about what this person has said, or to pick up the phone and tell his mother.