Just like it contributed to the decline of HOTS. (Google search Kendric silenced hots or Grubby silenced hots, the two most wholesome friendly players/streamers you could find. Silenced in HOTS=Ban on ranked play.)
You can make the game with no changes, but the culture the game exists in has changed to become much more sensitive. The definition of “harassment” has widened beyond recognition.
Vanilla’s emphasis on GM intervention saved many from being wrongfully banned for adverse behavior (camping towns, killing NPCs etc) but this will not be a factor in Classic, as demonstrated by HOTS’ (And new WOW’s) automated system where GM’s must be manually contacted in appeal efforts and rarely reverse the bans. Killing flight masters and quest NPCs in Camp Taurajo for 8 hours straight will be considered harassment/disruptive gameplay in 2018.
I am posting this as a historical reference for when my entire clan gets banned for PvPing, and I get to say “told you so.”