There is an adult way to escalate problems which is to first speak privately with the person in question to address the problem or correct the misunderstanding. If that fails, you could speak with people in the relevant social circle shared with Matthias. Dragging your problem into the public square is only something you do if those fail AND there are sufficiently good reasons to make it public.
Just to be clear: I am not defending or criticizing Matthias one way or another. I am speaking purely about process. This is a process that should be observed equally by those in positions of leadership toward those whom they serve in that role as well as the later toward the former. That is, both Matthias and Matthew.
This is one way to handle the problem, but certainly not the only way, and not a way that is blessed as "the mature solution". There are a variety of legtimate reasons not try to speak first privately to Matthias. Butterick gets at one of them in his essay, namely that allowing bullies to keep their bullying private has the effect of isolating other victims and preventing more coherent responses to it by a group.
It sounds like you don't have much experience dealing with abusers. I'd suggest reading, "Why Does He Do That? Inside the Minds of Angry and Controlling Men". Abusers will use private approaches like that as another opportunity to berate and dominate. Indeed, if you read the addenda to Butterick's piece, you'll see that Felleisen approached him privately and with "a strange mix of concilliation and hostility". That is also typical of abusers.
Your "adult" approach only works if the other person is also behaving as an "adult". Felleisen gave no indication to Butterick that he was capable of working at that level. If Felleisen wanted feedback, he could have signaled that.
Further, in the context of a project like this, bringing the behavior up to the people running it is generally a good place to start. The behaviors acceptable in a community are determined by the community. What Butterick learned was that abuse from Felleisen was considered normal and acceptable, and that the community would protect Felleisin over Butterick. In that circumstance, there's little point to approaching the abusive person because they already know they can keep doing what they want.
Instead of "just asking questions," then using that to make commentary that doesn't make sense because you don't know what's happening, try becoming familiar with the situation
There is an adult way to escalate problems which is to first speak privately with the person in question to address the problem or correct the misunderstanding. If that fails, you could speak with people in the relevant social circle shared with Matthias. Dragging your problem into the public square is only something you do if those fail AND there are sufficiently good reasons to make it public.
Just to be clear: I am not defending or criticizing Matthias one way or another. I am speaking purely about process. This is a process that should be observed equally by those in positions of leadership toward those whom they serve in that role as well as the later toward the former. That is, both Matthias and Matthew.