Do the existing rules prohibit people from debating the gender of people who identify as transgender?

Yup. Just like we lost a lot of posters over the board’s misogyny before policy finally changed, we’ve lost a lot of wonderful posters over transphobia. I know what the rules have always been. I hope the mods–old and new–are seriously considering making changes to rein in the board’s transphobia similar to the changes made to rein in the board’s misogyny.