Calling people out over knowledge of defense stat is a bit childish. I think even those of us who have no programming or math skills at all have still seen the relative inefficiency of the stat over years of play, even if we don't know the particulars.
As Chamann said, a Protect/cocoon type roll would be so bad if it cost nothing to use. But it costs an attack roll which in the scheme of things is significantly more valuable both in enmity generation and in killing efficiency over a modest reduction in damage.
At least a phalanx roll sometimes has a bit of usefulness (ex. pulling EP/DC mobs for a Fell Cleave party). A protectra roll would be a waste of a buff roll.