The company offers you money in exchange for signing certain agreements. You are free to decline. There is no obligation on either side.
If non disparagement clauses were illegal then perhaps the severance amounts would be smaller since there’s now much less value to the company.
>If non disparagement clauses were illegal then perhaps the severance amounts would be smaller since there’s now much less value to the company.
...and the salaries would be higher, and some people would be make different choices regarding whether they want to accept an offer or not.
They aren't illegal, but, like non-compete clauses, they should be.