The thing about DF is you're not guaranteed to get people who play the same way as you. There's no question that Cleric is the most efficient choice but you will find people that believe Protect is more in the spirit of being a "proper" healer. I find kicking over such a minor disagreement to be silly but it probably falls under "differences in playstyle" as being a valid reason.
On my Sch I have Protect in the first slot and I swap it for Cleric after casting it. The fairy is solo healing anyway so the party can keep going while my abilities are on cooldown.
On my Ast I have Cleric first. If the party wants Protect I explain I'll need to swap CC abilities and wait for my stuff to come off cooldown and they can decide if they want to wait or proceed.