Hopefully this is one of the things that we stop bringing up in the future. This donation was made by him, in his personal capacity. We only know about it because of political donation disclosure laws and it was dug out 4 years later.
There have been zero accusations or complaints that Brendan Eich harmed inclusivity as part of his job. It's a shame he was forced to step down, but we don't need to be bringing this up like it's a mark of shame on his part.
I didn't know much about him and Googled him out of curiosity to read about his affiliation with Mozilla. It is rather eye-catching to see "Known for: JavaScript, opposition to same-sex marriage[1][2][3][4]" under his photo.[0] Seems very easy to "bring up" unwillingly.