It looks like he intentionally played it in an embarrassing way that he would have more down time to derp around. Someone who is actually playing healer will avoid all overhealing and enmity generation possible, which is something that you can't do if your healing comes entirely from using Medica, Medica II, Regen on targets. I'm sure the tank had to work overtime to carry this "healer"
See above. If you are playing a DPS character, you have like 5 actions that you can roll through to maximize damage, and several DoT's that are either given by using those actions or as separate actions. Repeat.
If you are playing WHM, you can play ALL content using only Cure and Medica. If you want to give yourself some breathing space, Cure II and Regen work as long as the Tank says to use Regen on them. Otherwise you're just telling the mobs there's a tasty WHM who wants to be the tank.
Healing actually requires thinking about what to cast, not just constantly spamming the most powerful party heal and then sit back and do nothing. Maybe this is why Tanks think healers have so much down time, the people playing healers are trying to make the Tanks job harder than it needs to be.
