Since they are slow, it doesn't take that much time for them to be killed, especially if you have a small group of
or
attacking them with their strong ranged abilities. By making them immune to
, it gives them a better chance to live
a bit longer and be able to reach them. Anyway, generally, in the case of
, they generally need the intervention of
to activate their
, making
to fight
more often. High melee damage VS high health, sounds a good combination to me. Finally,
doesn't occur that much often after all so I really don't see why it would become a problem.