Some have hypothesized that Reddit was trying to increase their diversity numbers but it seems more likely that she's friends with someone or has a group of friends at Reddit and that's how she made it though whatever hiring process they have. Reddit doesn't strike me as the type of place that's very rigorous when it comes to process so knowing the right people might have been enough. Of course this is all conjecture.

A trans activist is a fantastic hire to brag about how diverse we are!

Yes I'm being cynical but why else hire someone with such a history for a social media company?

My question was answered by the CEO of reddit (well, I didn't ask him, but he answered it) in a post just 15 minutes ago: "As of today, the employee in question is no longer employed by Reddit. We built a relationship with her first as a mod and then through her contractor work on RPAN. We did not adequately vet her background before formally hiring he"

It's exactly as I thought. They thought they had a good employee and failed to vet with due diligence.

But, in their response, they absolutely failed to convince anybody: by banning a bunch of people for posting things that are in mainstream external media. Even if it doxxes your employee, once it's in the mainstream, you can't control it.