Yes in theory, no in practice. Such lawsuits are incredibly rare, and this sort of thing is often done with the explicit acquiescence of the board anyway! And in many places they just change the law to explicitly make it legal, like in the UK, where they passed an Equality Act actually makes discrimination legal.

Yes it harms corporations in both long and short term but the people who do it don't care, because their moral code states that corporate harm either isn't real or is actually a good thing. You can't win when arguing with someone's fundamental moral code.