And before people start with the "but corp UX is bad too" defence, of course that's true (and also quite irrelevant).
Open source, in many cases, is trying to reach the entire world. We need to work on making the software approachable and useful to everyone.
There are TONS of UX designers that are here right now, wanting to help but are rebuffed and told "they are doing it wrong" so guess what? They leave.
If OpenSource really is understaffed, that's a curious way to treat willing hands.
One last point: I'm not saying ALL #OpenSource software has bad UX! There are lots of positive examples. I'm just saying that, as a culture, it has some maturing to do. The very old and very tired advice of "go slow and try a small PR" works great for engineering (and documentation). I'm just saying that doesn't work for UX, which requires a more coordinated, shared teamwork approach.