THAC0 was not hated when it came out in 2e. Most of us were already using something very similar by then because it was easier than attack matrix tables, and freed up space on the character sheets to just have a single number. It first showed up in the 1e DMG at the back, so it was a natural progression. And it was an improvement over attack matrix by all but the most purist of grognards. Most of the hate towards 2e when it came out was the removal of assassins, half orcs, monks, and demons/devils. I don’t recall anyone getting upset about going to THAC0 from attack matrix.
No, it wasn’t hated until after 3e came out with ascending AC and fans of 3e looked back and liked ascending better now that they played D&D without THAC0 and got that experience.