This is not about the legal ownership. This is about operational ownership. All these maintainers understood what they signed. However, they expected to be supported to do their work mostly their way. For good reasons since other foundations do it that way. The .NET Foundation is however not communicating and supporting the community but focus on legal ownership including capabilities to enforce that (that is were some of the CoC and billing comments come from).

So it is mismatch of expectation. To blame is the foundation, because what you can read on the web page and the feedback of the maintainer community does not fit to their agenda so they could have understood this early and resolve it peacefully (they are the ones in power).

This is about open source leadership. They screwed up. Legally this is (mostly) fine, content wise it is (mostly) fine but the way how they operate is not okay. And saying sorry is not enough