We're well into the cargo cult layoffs. CEOs need to look good to their bosses and your job is a sacrafice they are willing to make. I'm sure there are some who will make their decisions based on real data and analysis - but they'll make thier decisions independently of other firms actions. Seeing all this clustered behavior suggests little analysis is really being done here.
Honestly, the tech industry was due for some churn from an employer perspective, and all this talent circulating is going to up the competition for company's products.