I've iterated this before many times here on the Farms, but as someone who was around when the "furries in IT" meme was actually a real thing the best way to explain it is that before the complete and total enshittification of the World Wide Web (for a multitude of reasons, pick your poison), "furries" were mostly just spergy and autistic white men and a few women who were into fantasy art. Since the guys were on the spectrum, they excelled at nerd shit like programming and the burgeoning web design industry. They wound up in IT because they had the skill set to get those jobs back when companies still hired you based on merit and not your pronouns.
This led to furries "running the Internet" by virtue of them being qualified for those roles, and this maintained for quite some time. It was very commonplace for furry websites to just be completely self-hosted and self-maintained by a staff of people who already had the skills to do all that and thus did not need to outsource it to someone else.
When the Internet started to go to shit, the wrong kinds of people got in and the bar for kicking around in the fandom and contributing to it was so low it was practically underground. Furries playing a big role in IT/STEM these days is really no longer true. They are just about everywhere because there is no cohesion and no shared "culture", as ridiculous as that sounds. Back in the 80's and 90's if you were into furry (then, "funny animals" or "anthopomorphics") you pretty much all read the same physical print comics and you went to the same Usenet groups and message boards. The world was a lot smaller. Everyone had that in common, you could ask someone what they thought about the latest Albedo or Wild Life or something and they'd probably have an answer.