Why do Some Argue Against Skill Based MM?

DeviouslyCursed:  Sorry if I've asked this before, but this chart, did it use the same number of games at each % for the good and bad players on the SBMM side? If not I would expect the highest players to have more games at the higher end. For instance more games at 55-60% than 40-45%, and the lowest players would be opposite and have more in the 40-45%. That could account for why low skilled players are losing more of the 'SBMM' range.