My gut feeling is that if you graphed all the performers’ public votes vs their quality of dance then on average the black dancers (not POC as a whole) have had less than their fair share of the votes. When you combine people who were robbed in the final (Natalie, Colin) and people who’ve been repeatedly saved in the bottom two because they didn’t really deserve to be there in the first place in dance ability (Jamelia, Simon, Heather) then I reckon black contestants were overrepresented. You can never prove it of course because there’s always a reason for each specific case (Natalie was a ringer, Darren Gough had huge narrative momentum, Jamelia said that thing about fat women). And Tameka and Chizzy and Melvin weren’t very good dancers (but they weren’t the worst dancers).
Of course there’s now a socking great counterexample in Ore who beat a better dancer fair and square on the public vote alone, but I still reckon on the history that white or mixed race performers have a slight edge in terms of access to the general public’s dialling fingers over black contestants.
Gay contestants OTOH, no evidence of that. With the exception of Colin who suffered from being in the closet so he had to sit there and take veiled homophobic jibes about airy fairy dancing, the GBP have always been happy to vote for gay men over and above their objective dance ability (Julian, Russell, Scott Mills for heaven sake). And it’s proven on umpteen other reality shows that the GBP are more than happy to vote for gay blokes. The Rev just suffered from being in a death slot and up against two much better comedy contestants on the night plus an excellent comedy number from Alijaz.