Consider the following scenario: you have just been paid $1000 and you go to an ATM. A dude at the atm mugs you. He sees the big deposit that has just hit your account and says "tell you what, I'll only steal $900. Then you'll still be up $100 overall". You should be fine with this right? You still made $100.

It's the same situation here. He took money that was due to one group of people and paid some of it to another group of people. This idea that if people make a net profit then it's basically ok even though he took some of their money is totally unsuported by the law for good reason.