That reasoning works until the judge considers damages. Then let's say it's a small developer, not too much work, and no commercial interest in the code. Damages are limited, in western law, to, well, damages. You need to have suffered a financial loss, the other party needs to have violated the license/contract/law/... and you need to show the causal connection between the two.

Let's say you contributed 500 lines of code to some project. You sue somebody for violating GPL and not publishing their changes. The judge has to give them the choice : either pay damages or actually comply (another western legal principle : money buys your way out of anything, as long as it isn't criminal).

What damages to assign ? Well, seems reasonable to say "how much for 500 lines of code ? A week's wages ? Okay, 2500 dollar damages awarded". The other party might become scared because other developers could conceivably sue, but ...