Sometimes you just gotta "trial by fire" people into learning proper support etiquette. Yeah I picked a healer/tank and am doing the best I can, but the second you start getting aggressive about me about it, you will suddenly see what it is actually like when I am no longer helping you specifically.

Speaking as a medic main there times where I go "well scout, solider or spy" if you did your job to protect from being ambushed from other pick classes I will heal you more.