Businesses need to be able to grow and shrink. Otherwise we just end up with "too big to fail".
A layoff this large means one of two things: the management screwed up on an epic scale (and should be the first to go) or it’s just giving investors a short-term stock boost at the expense of long-term success. Broad layoffs are usually bad for companies long-term because they signal both a lack of management skills and mean that everyone still working there is going to be worried about another round, so politics and making yourself harder to replace will consume a certain amount of otherwise productive time.
It must not be something impossible to do, but it must be hard. And they should favor most other courses of action.
But anyway, it's up to the government to enforce this, and the US (where they are hosted) seems to almost completely disagree. So we get those companies hiring like mad, just to fire like mad in a couple of years, and begin the cycle again a few years down.