In principle a lawsuit is just asking a neutral party to judge whether there indeed was a law breaking where I suspect there was one. Ideally, this is not a inherently hostile action that should be met with any negative consequences.
I know criminal and civil law are different beasts, but still the situation is analogous to renting out a room to someone in exchange for them promising not to report me to the police if I beat them up, else I can kick them out without notice.
It should be an inalienable right of anyone to report/sue for any wrongdoing against them. It should not be conditional on losing some (any) beneficial things.
"I agree I will not sue you even if I later find out that you did something illegal against me" should not be legal to be in a contract.