It is worth understanding that this is "different" than... all the other layoffs in tech at this point.
MS acquired ABK. Any acquisition almost always leads to "downsizing". At a high level: ABK would have had their own payroll department. Now they go through MS payroll. Why do you need an entire department whose job is now superfluous? Obviously this gets a LOT more complex with developers and the like (as well as local management) but that is the mindset.
But... holy fucking shit that is a lot of people getting laid off at one of the worst times to be unemployed in "tech" in the past decade.