Ridiculous strawman in the last sentence. A pic of a furry anime character is completely innocuous, and the only thing stopping acceptance of the service is intolerance. There really is no need to try to accommodate for the intolerant.
Like others have said, a simple rational response in the line of “yes, it initially shows an inappropriate branding for our purposes, but the nerds who made this like it. This branding does not take away from its suitability as a bot prevention tool, and the branding can be easily changed.”