99 times out of 100 it would be the player being cucked that people complain about. Netori is far less known and people seem to refer to it as "NTR but you're cucking somebody else."I wonder when people say "I hate NTR" if they mean Netorare (main character is being cucked) or Netori (Main character is cucking sombody) ?
Quite a few people have issues with Netori as well as Netorare, but yeah to answer your question it'll almost always be Netorare that they're refering to.