You are very close. They buy companies and convince a bank to refinance their operation. Now they start stripping that assets and the balance sheet looks like crap. Then they strip the remaining assets and the company is left with no assets, only debt.
Because they were so far in debt the banks are very willing to work with them because a huge loss like that is going to hurt the bank.
If you are only $1 million in debt you will be foreclosed on in a heartbeat. If you are $800 million in debt you will get special treatment because you are strangling the bank. The more debt you have the more control you have. That is, until a small creditor comes knocking for their money.