The whole 'responsible disclosure' preaching and the not-terribly-subtle threats seem particularly bad given that there's an entire industry of actively more dangerous people who are not only treated as legal but actively courted by state agents and cops(and often even less savory customers, though they tend to be cagey about those); the ones who actively seek to keep vulnerabilities quiet so that they can continue to sell exploit tools and services based on them. Throwing zero days on github isn't ideal vs. getting them fixed; but it gets them fixed faster than if Cellebrite wants to hang on to a bitlocker bypass or Trenchant, and L3Harris Technologies Company, wants to keep selling 'network investigative techniques' that can bypass default windows defender configurations or whatever the situation is.
From the outside it's hard to know whether MS actually mistreated the researcher badly enough to justify their displeasure(the consensus appears to be that MSRC was never the best to deal with and has actively gone downhill; but this person's position seems significantly angrier than average) or whether they are perhaps wound a little tight; but implying that their legal status is the same as people actively running attacks against user systems is blatantly false and totally ignores the class of researchers who do actively run attacks while being treated as respectable.
It's a particularly bad look when at least Facebook got into a public legal fight with the NSO group over their nerd-merc work against their users; not like that actually solved the problem of attacks on cellphones; but it was an all-too-rare case of industry pushing back against the 'respectable' arms dealers; and not one that MS has an analog to.