I'll temper my general "layoffs must be done without regard to performance" into a more specific "in this case, layoffs were done with at most marginal regard to performance".
Google and other big tech companies who participated in this round of layoffs explicitly ignored the most recent performance signal. They may have used older signal, but it clearly wasn't a significant driving factor. At most it may have been a tiebreaker if all else was equal. As noted in that link, seniority, redundancy, skills, and placement within the business were communicated to be the overwhelming factors.
Don't have access to that BI link, but it'd be pretty dunderheaded if MS did use layoffs for low performer housecleaning. Every time you let someone go because of low performance, you have a very non-negligible chance of that person suing you for how you conducted the termination. In the event of someone being _fired_ for low performance, their manager should have a clear paper trail documenting the low performance and the lack of improvement that led to their firing. That paper trail won't exist in the case of surprise layoffs. Doing that en masse would be opening yourself up to a hell of a class action suit.
It's also possible that people are saying layoffs not meaning the technical term, but to mean "fired a bunch of people in a small timespan". That was the Amazon business-as-usual approach, but it was called "unregretted attrition" rather than (correctly) firing or (incorrectly) layoffs.