It's clear from all the news and HN coverage that whoever is responsible for the layoffs put in absolutely zero thought about compassion and empathy. For some well-paid engineers those layoffs probably didn't have a large effect on their financial situation. For a lot of other people, they probably did.
Take Google for example. Instead of notifying people about their layoff, a lot had to find out that they don't have a job anymore by trying to swipe their badge at the office entrance. They couldn't even bother to send an email.
That said, you're right. I don't know what's going on inside Google. But I don't need to know all the internal details to see that hiring thousands of people and then letting them go just 2-3 years later is simply stupid planning. From OPs story it also looks pretty apparent that there is not enough internal communication. They've had a hiring freeze for months, then apparently lifted it, then let people go. What exactly is the logical reason behind that? What business reason could there possibly be to do that?
I don't stand to gain anything from defending them, but can we drop the hubris that almost any of us knows how these decisions are made at that level? I'm sure there's a C-suite or two skimming HN every once in a while, but most of us are regular old tech employees slinging code and talking to customers.
That doesn't make it any less awful for the people involved, and I feel for their situations.