They recommend crowdstrike to customers. Now they are trying to at least skim some good will. Also bad a kernel module that can ruin the OS is partially their fault.
Microsoft competes directly CrowdStrike with Defender across multiple areas - I'm not sure they recommend them to customer over their own products at the cost of losing sales.
I don't think Microsoft is realistically in a position to forbid other companies from writing kernel level modules, from an antitrust standpoint I would think that would land them under investigation(s)
I also think Microsoft should be responsible, they gave the keys to sign the kernel driver so I expect that driver to at least be subject to regular testing and scrutiny not just when initial release was made.
They didn't "give the keys", they have a signing infrastructure that is meant to be used for validating organizational identity and origins of code. They have a quality checking system, but it's only required for certain levels of Microsoft backing. I think it used to be called the Windows Logo Program or something?
You are right Microsoft are not checking the 3rd party code itself they are only running a lot of tests on the compiled code.
There is a recent video now from a former Microsoft employee where he explains that those drivers that get WHQL certification are ran on test machines in stress conditions for some time, or at least that is how it used to be when he worked there.
Since that process is probably quite slow to be able to push update within a couple hours Crowdstrike just bypassed the QA testing by injecting their own data files into the driver.
I don't think Microsoft is realistically in a position to forbid other companies from writing kernel level modules, from an antitrust standpoint I would think that would land them under investigation(s)