It doesn't matter if you share a profitable system or not. Firstly, most traders who pick up that system will not be able to use it profitably. But more importantly, there are no secret back doors into forex which make money for those who know about them.Which is more likely that a person is willing to try out a system?
1. profitable system
2. unprofitable system
Obviously, people would want to share their profitable systems. It's entirely a different matter whether the system is profitable or not. Then again, why would anyone willing to share their profitable system? They would throw in their kitchen sink in order to squeeze out as much profit from the market as possible.