Without knowing anything about economics or how they work, what crosses my mind and that is just a hypothesis, yet a plausible scenario, is that companies do this to maintain their financial validity due to current market turbulence of uncertainty...because if you think about it, if they don't show they are hiring, they will give the impression of stagnation, thus the loss of their current market value; but if they show they are hiring, without the outsiders knowing they are actually do not, it gives the false impression of company's growth, thus reassuring investors' financial concerns.
I hope I'm very wrong, but I have my doubts...