I could very well strip all comments and distribute just pyc files. Those can be reversed to commentless source, but it's not exactly as useful as the original

I could very well strip all comments and distribute just pyc files. Those can be reversed to commentless source, but it's not exactly as useful as the original source code. And honestly, anyone could clone the product just fine even without the source code. If you really want to fork the project, go for it. That's within your rights as per the GPL license. Just as long as you continue to abide by the license yourself. If your fork turns out to be better than my code, and more people end up using it, then you probably deserve any users you "take away" from me. If, on the other hand, you're just forking the code to be surly, then that's within your rights too.