I didn't see any references in the article you linked to any cases where it had been enforced. I see a lot of commentary that validates the concern, and a listing of half a dozen states where they are being struck down.
So the callout to be wary of them is totally legit... but it doesn't look like they are going to be enforceable when such things go through the courts.
Technically, maybe, but effectively, nobody is going to be able to withstand BigCorp's 100 lawyers whose mission is to bury you in legal fees if you push back. By the time that you confirm these things are unenforceable, you've spent your life savings on $millions in legal fees, and possibly gone into crippling debt. In the legal system, might (wealth + lawyer quantity) makes right.