I think the disagreement is one of policy. The Moodle integration policy is that bugs should whenever possible be backported to all versions released in the last year. Security bugs are backported for another year or longer for LTS. So Moodle developers and admins expect this. If you submit a core fix for Moodle integration that policy is not debatable.
The policy is not necessarily shared by other user communities. H5P is used on other platforms, and H5P core team detemine their own policy. If one is submitting a patch for an H5P core content type, one should follow their rules.