They are.
Personally, I think the law should require that nondisclosure agreements should be strictly time-bound[0], ban all non-disparagement agreements[1], and replace binding arbitration with non-binding arbitration or mediation[2] that can still be escalated to a court if it breaks down.
[0] by how much I am uncertain, but outside of national security considerations I can't think of anything that needs to last longer than a patent would have.
[1] Two arguments: (a) basic freedom of speech; (b) I am British by birth. The UK is so famous for being an easy place to sue for libel that the US passed laws making fines from British courts non-enforceable in the US; why then does the US allow private companies to insert the same effect via contract? https://en.wikipedia.org/wiki/Libel_tourism#United_States
[2] Court cases are really expensive for everyone. Arbitration is much cheaper and this itself can absolutely benefit workers and customers.