> Please provide a definition according to which not disparaging constitutes a service.

Happy to. A service is any activity that one party performs (or refrains from performing) in exchange for consideration from another. That's basic contract law. Every lawyer learns this in 1L.

> it makes blackmail a "service"

No, because blackmail involves a threat to do something you have no right to do, or a threat to reveal information as leverage. A company offering severance isn't threatening you with anything. They're offering you money you aren't otherwise entitled to. You're free to walk away with nothing and disparage to your heart's content.

> you're conflating legal and moral arguments

I'd say that's been your move this entire thread. You keep asserting that severance is compensation for past work as though it's a legal fact, when legally it isn't. It's a voluntary offer. Then when the legal framework doesn't support you, you pivot to "well it's a basic expectation," which is a moral argument. I'm fine having either conversation, but pick one.

> It's not restricting factual statements

Agreed that overbroad non-disparagement clauses are bad. But "this clause is sometimes too broad" and "this clause is inherently coercive" are very different claims, and you've been arguing the latter.