depends on the item really, if a healer needs on spell damage gear that a caster needs hes gonna have a rough time, which is good, cuz hes not only most likely an idiot, but also an asshole. Ignorance=/=Innocense.
If a Hunter for example goes UBRS and needs on Truestrike, that is totally understandable, while the warrior is stuck with those shoulders untill AQ, and the hunter will instantly replace them in MC, it is fair game, why else would the hunter join the run if he is never allowed to need on anything just because warrior Tier 1+2 sucks for DPS.
Briarwood reed is an example of a Spell Damage item that healers genuinly have no alternative for, Second Wind + Briarwood Reed is also their Pre-bis, so ofc the healer should be allowed to roll.
But if a healer took my Hands of Power, holy hell, my petty personality would probably kick into overdrive, and i could easily spend and hour or two on childish shit like mailing him 50000 individual arrows, and the screen shot would be passed around quite a few discords. that would be such a dick move it isn't even funny.