They do go out of their way to remind us that Ice King is motivated by loneliness.
If you want to be one of those insufferable parents who talks about TV with their kids, Ice King is a cautionary tale about what happens if you don't take turns and share. I don't recommend the "mean people just want to be loved" moral; the implication of that one is that, either you are giving mean classmates another chance all the time, or else you are part of the problem.