> So, in America, just because it's written in a contract does not mean it's enforceable in anyway.

But the presumption, as any court will show, is that it is fully blooming enforceable. The burden of proof is on showing it isn't. This particular instance, a lawyer would laugh at you in the face over, this is absolutely 100% stone cold enforceable common and expected.

How do you expect Facebook or HN to moderate if certain uses aren't prohibited? The same principle applies. HN bans certain phrases, lots of them.