That only works because Kimmy Dee has told us she is female. If we were talking about Alex Ample whose gender we do not know, because they haven't told us, then it is perfectly correct to use "they" and not arbitrarily assign Alex with a gender we can not know. If Alex was playing a female character in an MMO, then I would probably refer to them as "she" because they have presented as female, unless Alex corrected me otherwise, or stick to the neutral singular "they/them"
