They all include a NDA about the agreement itself. So yes, the terms are confidential. Even the fact that a particular that you may or may not have an agreement at all is confidential.
With respect to the fact of the existence of an agreement being confidential information, usually an NDA will only apply to information that has not already become public through no fault of either party.
Every Master Service Agreement (MSA) I’ve seen has had a ton of legal back and forth. To say that they all include NDAs is a generalization which isn’t even mostly true in my experience.