I don't think this had anything to do with that incident, as Zach worked at GitHub for a long time (years?) after it happened. Here's an excerpt from GitHub's internal investigation which talks about the allegations other than those alleged against Tom Preston-Werner:
> As to the remaining allegations, the investigation found no evidence of gender-based discrimination, harassment, retaliation, or abuse.
That's just the public report. It is perfectly consistent for a company to publicly say nothing wrong occurred, while quietly firing some of the few individuals involved. Personally, the sudden-ness and lack of reasons for firing lead me to suspect it was a reason.
I realize this is unsubstantiated speculation on my part, so take this all with a grain of salt.
> As to the remaining allegations, the investigation found no evidence of gender-based discrimination, harassment, retaliation, or abuse.
https://github.com/blog/1823-results-of-the-github-investiga...