IMO the fault lies 100% at CrowdStrike. The software does not only run on mission critical systems, but also one such systems, where a automatic update is okay and even wanted, where the operators maybe just don't have the capacity to run tests before that. Many people trust CrowdStrike, and yeah, sure, everyone should do tests before updates in a perfect world, but in reality (as we now see) this is not always the case. Not because people are actively sabotaging themselves, but often the priorities are somewhere else, that's why they are using high-quality software, and trust their automatic updates to not cause a total blackout.

I install software -> PC crashes and can't recover itself -> it's the Software's fault. Sure, I could have prevented it, but this doesn't change who's at fault.