the real problem is more simple than that......they just cant read properly.
they think its also a damage reduction, but us people that can read know this is infact only for pvp and not pve.
personally i agree with you, it should always be put on the dps, and if one of the dps is a powertech he should get priority as they are the only ones that dont have an aggro dump (juggs also i think) as i play powertech dps i find it so god dam annoying, constantly gimping my dps so i dont pull aggro
ps. the reason you end up tanking is because u r bad, a good dps will not pull aggro :P control your output, simple as that.