Clubs turn to people like MSD when they're already in dire straits so you're quite right to have thought that. This was actually Dell, giving a high interest loan, whereas FFP didn't involve Dell and was intended as a purchase of the club, Glenn Fuhrman was the driving force to buy Sunderland. Derby, Southampton and Burnley all have loans from MSD although the Burnley situation is more complicated. Southampton are paying back around £8m a year in interest alone.
FFP and MSD are two different entities but, it's fair to say, I feel much happier with KLD than I would with either of those.
FFP wanted to own SAFC but, it would seem, came to realise that loaning money was a safer idea. It brings in multi-millions and they'll probably end up with a club for peanuts by default. 'Burnley' have mortgaged the ground to MSD for around £60m and Southampton have mortgaged their ground and other assets for around £80m. Now that Derby, who have borrowed around £50m at a guess, have gone into admin it looks like MSD could become owners for the cost of the loan unless someone else steps in to buy the club. 'Derby', from memory, mortgaged the ground then the training ground when the first loan ran out. When I say Derby took out the loan I believe it's actually the company that bought the stadium which is really messy imo.
It's all sad and worrying, as you say we should thank our lucky stars we have the owner we do.