What exactly provoked the mass migration from Freenode to Libera.Chat a couple years ago?

I keep seeing references from early 2021 talking about something that happened at Freenode at the time, and that whoever was running it did something that upset a lot of people. A large number of free software projects (including a bunch of distros and the FSF) seemed to migrate from Freenode to Libera Chat, there were apparently a large number of resignations, and Freenode apparently seized 700+ project channels from their developers.

I wasn't using IRC at the time, so I'm very confused about what exactly happened. Hopefully someone can clarify this for me: What exactly was everyone so angry about? The Wikipedia article just says that there was a "hostile takeover" of the network by Christel Dahlskjaer. I understand why that would make the volunteers upset, but why would a bunch of open-source projects care about that when they just used the network as a means of communication? What did this guy do (aside from seizing their channels) that pissed them off? Most projects (from what I've seen) announced their migration to Libera Chat before their channels were seized, and the seizing was done in retaliation (at least that's what the FSF says