I have a tank.
I have decent gear.
I tried ranked.
I was chewed out for not doing hard guard switch and only guarding the healer.
This was the second time I tried ranked.
I have not tried again.
People should definitely try not to be jerks about it, but they did teach you something you didn't know. Why would you not take this new information and try again? Quitting ranked altogether because someone was mean is, well, silly. Why limit your access to the game because of a couple random people?
Did you at least go back to unranked and put this information to use instead?