He helped strip a civil right from gay people. That's discriminatory treatment. More evidence is not needed for people to have a reasonable fear of further discrimination.
"We haven't detected X, ergo X doesn't exist" is an obviously false notion. It's false even in the same situation, but it's even more obviously wrong in a different one. As CTO, he would have had a hard time making a bigoted technical decision. But as CEO, he's in charge of all sorts of stuff where a subtle bias could be expressed, and there's no longer an executive above him who could hold him accountable.
"We haven't detected X, ergo X doesn't exist" is an obviously false notion. It's false even in the same situation, but it's even more obviously wrong in a different one. As CTO, he would have had a hard time making a bigoted technical decision. But as CEO, he's in charge of all sorts of stuff where a subtle bias could be expressed, and there's no longer an executive above him who could hold him accountable.