If all political views are valid, what about someone that has documented pro-segregation views? Is that person qualified to make decisions that impact the lives of a diverse workforce? If not, where do you draw the line? I'm not trying to make a strawman argument - I'm seriously asking why would this be any different?
The problem isn't that he had some thought in his head - its that he took that thought in his head and turned it into action. And those publicly documented actions made it impossible for his employees to trust him to make decisions in their best interest. Having the trust of his employees is 100% part of his job - the fact that he lacked that made him unfit to be CEO.
Supporting something that turns out to be unconstitutional clearly shouldn't be a fireable offense. But, both of the examples you cite are cases where a person can cite reasonable reason for their support that aren't merely about controlling the lives of others for no purpose. I probably made a mistake in mentioning it was overturned at all - I'm just saying, he continued to argue for something that wasn't even relevant anymore - in 2014 when this controversy erupted, same sex marriages were actively occurring in California. It seems likely that some of his employees may have benefited from this. And, yet, in 2014 he continued to support the prohibition of same-sex marriage - actively advocating against the life choices that his employees were making at that very time.