(The title you see below mine is the wording chosen by the OP of the full post - I hope I do not cause offense, but I cannot control it showing up here as it is linked.)
The comment is far less calm than you would have us believe. I think it just resonated with your own frustrations. That doesn't make it good in any way.
I see it as a call for people to be able to discuss things calmly and rationally. Certain facts within the statement e.g. "get called an idiot shitlib and told to read some theory" are definitely emotionally provocative (as are terms such as "everything" and "nothing"), but indeed that happens sometimes, i.e. everything is relative.
Do you mean himself? Indeed he is the only one who can control the situation, e.g. by blocking them. On the other hand, OP (of the OP I mean, not the commenter promoted here) was a new member of Lemmy, so was shocked to see this behavior, and wanted reassurance and a community of like-minded people to stand with them.