There is theory out there stating that individuals that act rationally would take the alternative that is more beneficial for them. In the case of money, particularly when it is lots of money, it is easy to forget any moral barrier to this.

So, I am the owner of an exchange. I have 1 Million bitcoins from people on the exchange and my business is giving me around 1 million a year in fees after covering the expenses. If I hack my own exchange I will make 100 years profit instantly, and since it is not really regulated, the risk is minimal.

Here we go!