I mean, dumber things have happened. Governments have destroyed their own government buildings to blame on the opposition and gain sympathy for their causes.
Yes, false flags. That's usually used to motivate people to go attack someone or to garner sympathy or support for a cause. MS's products being subject to attacks because they have numerous vulnerabilities does not encourage anyone to go out and buy other MS products.
You sink one of your own naval vessels (or it sinks due to an accident and you take advantage of the situation) and blame it on an enemy. That enemy is now the target of your military and your population approves.
A shipbuilder hires someone to poke a hole in 1000 of their ships that are so badly designed and manufactured that it only takes a rubber ducky bouncing off the hull to sink them does not encourage anyone to go back to that shipbuilder.
False flags (particularly of the "let's kill or maim hundreds of our own people and other innocent people" variety) push into evil territory. They aren't dumb on their own, they're calculated risks predicated on the willingness of the masses to fall in line after a catastrophe.
Deliberately hurting your own customers by using weaknesses in your own systems in order to motivate them to go buy your other products or services is dumb.
I mean, there are definitely stupid people everywhere, but I'd hope MS leadership isn't that stupid.