Is it really shooting itself in the foot, though? There are plenty of FOSS projects that companies benefit from and never contribute back to, either monetarily, or in the form of writing code. They provide an easy option to make it look more professional while helping to support the project, and you could always fork it and do what you need to with your fork. The idea that developers should do a thankless job to maintain their software in a way that complies with random corporate policies in order to be more widely adopted strikes me as setting up devs to burn out and crash from having all the joy ground out of their projects for them.

UNESCO, the Wikimedia foundation and other major organizations have already implemented it and gotten onboard, so I would suggest your coworkers are being a bit foolish in completely disregarding it because of a single mascot image that has a clear option to replace. The Dev is just saving themselves aggravation from people that were going to make endless demands of them, but most likely balk at actually supporting the project to enable features that only matter to their organization, but not to the Dev themselves or others.