That article doesn’t remotely suggest that they are “bad”.

The article says they were advised by Deutsche Bank that they could classify certain trades in a way as to pay long-term instead of short-term capital gains taxes.

The IRS disagreed, RenTech went through an appeals process and eventually decided to settle instead of continuing the process.

There’s nothing evil about trying to legally lower your tax obligations and then being told by the IRS “Nope, you can’t do it like that.”