I’m assuming you’re talking about scourge ranks and the like. Necrolytes were most prominent as orc necromancers in the first war, weilding magics that fall under a general “bad” label. They would probably be regarded early warlocks with the typical demon inspired necromancy of the later Scourge.
Acolyte is just an entry level churchly title not inherently bad. The Cult of the Damned under the Scourge use the acolyte title for their rank and file cultists.