Why is that illegal? Why doesn't it just get you kicked from the market if you do it?
If we are playing poker, and you cheat, you have stolen my money through fraud.
Certainly if I cheat at a casino, I'm likely going to jail.
Also, perhaps there is a differentiation between working within the mechanics of a system to cheat, and going around a system to cheat. An example from the esports league would be the difference between using a corner case to shoot through a wall, versus hacking into the server and modifying the code.
That isn't the definition of stealing. In fact I would argue, while it is dishonest, it isn't stealing in slightest. Stealing means you took something, without agreement, that rightfully belongs to someone else. The scheme is more accurately described as fraud than stealing.