[PeterisP]

That's not really help that contributes to the project, that's communication or (often in the case of usability issues) opinion that might be useful, and even if it is, it just piles on more work on the project instead of helping with that work.

Every project has accepted everything whenever I've actually tried to help with the actual work they're doing, i.e. solving a bug or submitting a pull request fixing some documentation, something that reduces their todo-list instead of adding to it.