It’s harder for healers to climb the ladder and get rewards.
Currently, in NA, there are 121 players above 2400 in RSS. Out of those 121 players, only 3 are healers.
118 DPS vs. 3 healers.
When a DPS goes 0-6, it means nobody managed to carry them. The healers go 3-3 and get 0 rating. The other 3 DPS go 4-2 and get rating, even though they also couldn’t carry the 0-6 DPS.
Healers are in a pseudo-1v1 duel. They’re about the same rating, so they’re likely to go 3-3.
Frequent 3-3 and 0 rating games is a poor experience. Healers play a more stressful role, they put forth significant effort trying to keep teammates alive in high dampening, and then they end up with 0 rating.
When a healer goes 2-4, it’s commonly because a DPS randomly made a critical error when they were on that healer’s team. Healers feel like they have less agency over the outcome of a match and they’re at the whims of the DPS.