You missed a huge detail there... it was cleared in hours by a guild who has been practicing for years*.
Most classic players have not done that... most guilds will NOT clear naxx in one raid night. Making judgements on content based on speedruns is maximum pepega and will always be.
The only way to make a fair comparison between classic and retail is to compare classic raids with mythic farm raids. Even then its skewed against classic because of years of practice, even retail mythic bosses are farmed by world first guilds within a single night after they have killed them like twice. Which at most is... 2 weeks?
The power of practice.

Still... world first guilds =/= general population. Naxx might be easy for the best guilds but not as easy as you think for everyone else. I bet most people here bashing naxx dont even play classic, if they tried they would probably end up wiping alot and crying to their raidmembers "but its supposed to be easy! the world first guild did it in less than 2 hours!".
