Could you link to that? He has stated that his giving to prop 8 was not "evidence of animosity" and did not make him "hateful" or "a bigot"[0]. Not a surprising position for him to take regardless of its correctness: I don't know many people who'd call themselves hateful and bigoted even if that applied.
But to my knowledge, he has not at any point apologised for giving to Prop 8, quite the opposite.
> Has he publicly opposed gay marriage in some other way since then? No? Okay…
His donations to prop 8 were not public in the first place, the donation lists (of both sides) were leaked. I'm not sure how that's relevant though, he's not changed his mind since then.
> ...let's not forget that around 90% of the language in the '64 Civil Rights Act was around repealing existing discriminatory laws
I'm not sure what you're trying to say here.
[0] https://brendaneich.com/2012/04/community-and-diversity/