Just screams unprofessionalism in my opinion.
Surely the guy not paying is the unprofessional one?
Sure, since "he signed", he could have probably taken legal action, but that's often a long and costly process. How is cutting your losses and walking away (but outsourcing the code you wrote) unprofessional?
Surely, both people in the relationship can behave unprofessionally.
> How is cutting your losses and walking away (but outsourcing the code you wrote) unprofessional?
That's not why people are suggesting the developer is unprofessional. It's because he's complaining about a client publicly.
Just saying the word "professionalism" doesn't make you the one who is more professiional, or make your concept of professinalism the better one.
I think there is a different way to phrase this, something like “this is the result of a collaboration that didn’t end up working out” or whatever. I get that it’s kind of mealy mouthed, but it avoids any aura of conflict in the evaluation.