My guess is the founder was frantically trying to raise money somewhere. That would make such behavior slightly more rational, I suppose, though no less criminal.
That would both make it feel more ethical to the founder ("I'm just bridging the gap!") and look less useless ("If I can make it to Friday they'll get all the backpay, there's no problem!"). Without new money on the horizon it's simply incoherent, to say nothing of immoral.
Of course, none of that makes it right. There are plenty of startups that handle this without cheating successfully. I've gotten the phone call saying "we can't pay you now, but here's our fundraising schedule and when we expect to have money". It might lose you some staff, but I think it's not as bad as most people expect - either the situation looks good and people stay, or the situation looks bad and you weren't going to save the company regardless.
I am sure it's an uncommon story but in his case the hustle worked out for him. In short it doesn't look good but sometimes at least it works.