How is the concept of mesorah harmed by saying that minhagim were influenced by bigotry towards women?
Furthermore, if by bigotry you mean sexism (as opposed to misogyny) then they are correct. Many halachos are sexist (e.g. a woman cannot be an Eid for many matters). As long as that doesn’t mean that the halachos are invalid, how does it damage the mesorah.
I don’t know or care what “bigotry” or “sexist” means, but if someone were to say or even imply that any halachos or mesorah or minhagim are wrong or bad or mistaken or ought to be modified, they are violating numerous issurim.