It is true that the system as it stands currently does incentivise bad behaviour. By bad behaviour, I mean actions that both transgress broader moral norms, and are detrimental to the longevity the system itself.

But, it is also true that unethical behaviour in that context can legitimately still be seen as unethical, and therefore attract moral condemnation. The fact that the system incentivises such behaviour does not remove anyone's moral responsibility.

For example, a society that incentivises violence against children is not what I would call a good system. It's also completely coherent to say that individuals committing the violent acts are doing the wrong thing. The only people interested in excuses are cultural relativists and the aggressors themselves. People with a more firm idea of the ethics of that situation, whether they are part of that society or not, will not run such a line of reasoning.

As you correctly observe, a more relevant example is the commons dilemma. Overuse of a common un-owned or collectively owned resource might be incentivised by the context it occurs in. Yes, it is true that a good system would not do this. But it's also true that fairly rational good people (by which I mean minimally good, not 'moral saints', with a bit of common sense) would recognise this and act to change the system and restrain themselves to maintain equilibrium while redesigning the relevant parameters.

I guess you and I differ in that I don't think maximising profit at the ultimate expense of the system that creates it is rational. I agree that the system is flawed and that desirable behaviour that is good for the platform should align with profit maximisation. But none of the people involved in fucking it up, regardless of the size of their stake, get to absolve themselves of moral responsibility.