It's the same BS internet myth that "rewards one tricks" in general, then the forums are full of one-trick DPS who are put in groups of one-trick DPS all the time and can't climb because they lack the necessary skillset to be a bit more flexible. And the reality that the 'skill' part of the SR reward for that particular hero amounts to about 3-5 SR difference per match; the biggest impact being made by the hidden MMR value and the odds the system gave you when the groups were formed.