I don't think it's as bad as everyone else does.

If, instead of getting the missed wages after 6 months, you were offered equity equal to the wages you were missing, would that be fair?

In the end, that's the same deal, assuming you could buy equity. (That isn't necessarily true, though.) If the company survives, you get your money in both situations. If the company doesn't survive, you don't get your money in both situations.

If you still think it's not fair, ask for equity instead. But they apparently just don't have the money right now, so they couldn't possibly pay you more to start.