Depends on the situation. It seems kind of silly to insist that such a label for beings such as Molag Bal (a dominator and corrupter) and Potema (considered in-universe to be one of the few beings that could be considered unambiguously evil) and Mannimarco (a selfish, power-obsessed necromancer who enthralls people just to sate his own morbid fascination with power, whose followers enjoy making their victims suffer) is somehow erroneous. Just because it's mostly grey and gray morality does not mean that beings cannot have combinations of characteristics that are generally viewed as evil.
On the other hand, I do think that in some cases, the label is misapplied, in-universe and out-of-universe.