This whole thing sounds more like a way to get some pull requests to fix their product for free. That's not open source. The source code is simply available, that's all. In the first run they even prohibited to fork it (!!!) while it is necessary to work on this project. They may fixed it, but you are still not allowed to do anything with it, only provide free work. Of course people are not happy with it.
They should delete this repo and change their license if they want contributors for free. Or just hire programmers for money.