A few of the people in that group (but none on the technical board) have been contributing to projects and then disappear once the IRCv3 bits are included. Thusly it appears from a broad glance that they had no interest in the project itself as much as getting another client onboarded with IRCv3 support.

This in combination with the marketing efforts of the IRCv3 group places large amounts of pressure to just accept and maintain the patch in order to ensure that you wind up on their list of recommended software to use, instead of their advocacy of using a different software which has added the patches.

I fail to see the issue. They fixed your project to stay compatible with the spec. They didn't stay, but isn't this the behavior of anyone who just fixes an issue they had in a project?