So basically RP received quite a lot of hate for not including drag kings, bio queens, transqueens or any other 'variation' of drag. Ru has since said that he is only looking for talent (and charisma, uniqueness and nerve) and is happy for transqueens to compete providing they haven't started surgery (such as Monique, Peppermint and Gia). Loads of people have been pushing them to including transitioning queen's and bio queens as drag is an art form (keep in mind here that drag literally means "dressed as a girl").
Carmen Carrera (who was a contestant on RPDR season 3) has kicked off because the new line up for season 12 has been revealed and there are no transqueens, drag kings or bio queens again. So they're not saying that even with all the facts Ru still isn't being inclusive and therefore clearly doesn't see any value in other variations of drag. Carmen was a gay man on the show but came out as trans after her season and has now fully(?) transitioned.
Contestants on the show who look like women without tones of makeup (looking at you Courtney Act and Derrek Berry) have been criticised by the judges for not being 'draggy' enough. It's very clear what they are looking for and it is not the most convincing woman impersonator, but look is an important factor. I think Ru said having women and transwomen on the show competing wouldn't be fair as they don't go through the transformation, therefore they would have longer to work on their makeup or skills before the main stage or before their main challenge as they don't need to tuck or contour breasts etc. Plus most bio women don't need to create a female face from a man's face (soften their features, hide stubble etc). He compared it to using roids at the Olympic I think... Or performance enhancing drugs of some description.