It may seem like a pedantic difference but you are missing a key part of what's going on here. Nobody is challenging that gender dysphoria is a bad thing to experience... This policy is saying it's kosher to proclaim "transness is a mental illness" which means in effect that encompasses gender euphoria and all expressions of gender incongruity as symptoms of a mental illness. It's a subtle linguistic difference but one makes it possible to publicly derride trans people as being delusional or harmful to people around them or dangers to themselves and push for "curing" all transness by approaching being trans as a failure state.