Casey did choose to help - explaining the issue and potential solution on github. It was only after his solution was dismissed, then catching the microsoft engineers using his solution and making a blog post about it that he complained.
they were not caught using his solution. they published a blog entry describing that they were made aware of performance problems and they didn't mention him. it was rabid fans of Casey that started foaming at the mouth then, even though Casey publicly stated he didn't want or need credit, because the idea wasn't his to begin with.
For anyone interested about the blog post drama check https://twitter.com/cmuratori/status/1522468481135902725 (hn discussion: https://news.ycombinator.com/item?id=31284419)
Personally I think that he owes them nothing, especially after the way he was treated in https://github.com/microsoft/terminal/issues/10362 so I can't comprehend statements which claim that he was an asshole for using GPL.
I'm saying he could have helped the situation, and he deliberately chose to not only avoid helping, but to hinder anyone at Microsoft who wanted to look at that code and contribute to Windows Terminal. That was a choice he made intentionally.
He could have taken the high road, there. He chose not to. It's his choice, don't get me wrong, he was well within his rights. I just disagree with that choice. that's why I call that a "dick move". And if you disagree with me, that's fine. "Dick move" means different things to different people at different times.