Because the PE firm had partners who bought the underlying real estate for themselves.

I'm sure that there are PE firms that really do try to make businesses successful and profitable, but the vast majority are in it to sell off anything of value and dump all the ensuing debt into a company that will shortly go bankrupt.

If you own a company, and a PE firm buys one of your clients, that should be a hint to require prepayment for everything they ask for after that. They will leave you holding the bag as a creditor.