The problem is that those mechanics inevitably are made in ways that DPS can deflect responsibility.
Case in point –
The DOT mechanics on 2nd rookery boss is theoretically a mostly DPS mechanic, but it’s easier for the tank to just take responsibility for it.
Before long, the tank is expected to be the one doing it.
Or the countless mechanics that DPS should be doing, but when they fail, they take massive damage. Not instadeath, so it’s suddenly a healer problem, and if they DO die, it was the healers fault.
To your last point, DPS should absolutely be mostly responsible for mechanics, and they should be designed in ways that make it impossible to shirk that responsibility, or they will.
Tanks are always saddled with positioning the boss, swaps and other tank mechanics in raid, and routing in mplus. Healers are saddled with healing. Only fair that DPS get something unfun to go with their dosing fun.