That's not even the issue. Nobody cares that MS is using ffmpeg. It's just rude to have as much money as MS does, integrate ffmpeg into one of their core products, then apparently not know anything about it and file hilariously bad bug reports that are actually just support requests after never contributing anything back.

Like, I've used ffmpeg probably since it was released. I've never given the ffmpeg developers anything, and I expect nothing in return from them. They don't know me, they don't know I exist, they don't know I use their software. I could not reasonably file a support request as a bug like they did and expect to be taken seriously. Why does Microsoft get to have this expectation when they behave the same way? They're a big company who asked ffmpeg to do extra work to support MS's ignorance and laziness, and they didn't even offer an ongoing support relationship. They wanted to throw a few grand at ffmpeg once to make the problem go away. This is completely ridiculous.

If they release a software package with a license that explicitly states that they allow the whole world to use it freely without any expectation if return, they cannot complain afterwards that some particular people in the world end up using it. ... likewise for bug reports

Literal nonsense. If someone abuses my bug tracker to act like a clown, I have every right to decline their support requests, even if I licensed my software open source. Nothing in open source philosophy requires you to bend over backwards to cater to every MS project manager's poorly thought-out whims. You're literally just making things up.