Having read the article but not knowing anything about the posts themselves, I think most of this thread misses the point.

Clearly Microsoft knew it was hosting Gab and what Gab was. There's a troll argument that suggests Gab is just "free speech twitter", but of course that's not the case: I've been screenshotting the front page for months, from a random anonymous account, and every time I've done it the front page was full of horrible Islamophobic, racist, and anti-Semitic crap. That and bot content.

My point here is: everybody knows that's what Gab is. Microsoft isn't pushing back on Gab's anti-Semitism --- without anti-Semitism, there is no Gab. They had specific harm reduction problems with a pair of posts, one of which, according to this article, was a call for violence directed towards Jewish people.