Maybe Microsoft encouraged Delta to use Crowdstrike, then ok I could see the case.
But if it is anything related to how Windows works, that seems like a stretch. Yes Windows could be better, but I don't like the idea that the OS provider could be sued for a piece of software causing problems. That seems... dangerous.
Regarding Delta. This seems like an interesting situation. Apparently Crowdstrike offered people to help, but how many people and where. Realistically how much help would they have been able to help given that it isn't like this was isolated to Delta and I imagine their people were stretched pretty thin. And importantly what exactly was the help provided. I don't see any information about this.
While I am sure that Delta's IT department was understaffed, this was also a unique situation. If you spent the time to make a well optimized machine for rolling out updates, things were automated, and you expected things to go wrong but I would have never anticipated every Windows machine being unable to boot. That is an extra-ordinary situation. I doubt any IT department is really staffed to be able to handle that situation happening. You don't expect to need to deal with every machine you have, its honestly kinda unrealistic.
It will be interesting to watch this one play out in the courts. Because at the end of the day the vast majority of the blame for this entire situation is on Crowdstrike. The companies were handed a situation that we were not prepared for.