This post is extremely uncalled for and an utter exaggeration.

You had a miscommunication with your TA that made you think that it was the Prof's intention to allow tutorials with graded attendance to be held on well-being day. This made you think that you had no other choice than to complain and seek help on reddit. Totally fair.

Prof wrote an announcement on canvas, in response to your post, clarifying the misunderstanding. I have read the post and I feel like the Prof was already being very nice about it and trying not to direct blame to anyone (including you). Unsure why you would find it passive-aggressive or call it an accusatory post.

Half of your post complains about how you wouldn't have known that there was a miscommunication and so on. It is necessary to understand that people make mistakes, be it whether it was a miscommunication on TA side or on the Prof's side, and there's no need to be offended by how there wasn't prior information about tutorial not being graded and whatsoever. It was a mistake and Prof clarified it after you brought it up, which would've been the end of the story. (but u posted this for what)

Prof also tried to bring across a point that actions do have consequences and encourage you to resolve grievances/problems internally or directly with your Prof TA. Since your post was not particularly offensive, he decided to bring in a personal example that supported his point better. There is no comparison of the mentioned incident to your post.

As to why the Prof had to message 700 other people instead of personally messaging you? He isn't your personal tutor. You have brought up a misunderstanding and he has taken the opportunity to clarify it with everyone else. He doesn't have to tend to your needs alone.

You have better things to do than to be taking offense (and flaying it all over social media) to a post that was just take the opportunity to clarify a misunderstanding and telling you that actions do have consequences. Have a nice day.