The only people who argue against this that even bother to offer a reason are usually just posting some fearmongering hyperbolic nonsense about the destruction of the economy (ignoring that numerous people are already farming with 8 player loot constantly and many items are still 1 in hundreds of thousands in some cases even with 8 players).
For the lazier naysayers it’s always just “go play single player,” which is immensely stupid as a response since the people who want this aren’t claiming to play solo 100% of the time. They just want it for farming for the most part (although it also offers additional difficulty for playing through all difficulties if you want). Most people are solo farming, even when they’re in a game with more players.
People who farm in 8 player games are not even playing this game together. They are doing split runs and just using each other for buffed drops. That is not “social” or an important multiplayer aspect by any stretch of anyone’s imagination.
Players command online just evens the farming playing field without having to hijack games or find split groups on a third party app.
It’s also a massive substantial difference without it.
Some random comparisons:
Ber rune drop chance from a normal ghost on hell difficulty - 1:355,624 with 1 player, 8 players - 1:106,003. That is a 3.35x higher chance going from 1 player to 8.
Ber from boss mobs: highest non-quest drop is Izual and Nihlathak. 1:54781 and 1:55,705 on 1 players, 1: 37, 434 and 1: 38,354 on 8 players. 1.46x and 1.45x difference.
Shako from normal hell mobs - hell bovine on 8 players 1: 619,511, with 1 player - 1: 2,403,475. 3.87x difference.
Shako from bosses: On hell with 1 player: Andy 1:1817, Meph 1: 1842, Diablo 1: 1893
8 players: Andy 1: 995 (1.8x difference), Meph 1: 1501 (1.2x diff), Diablo 1:1543 (1.2x diff)
Those numbers are 0 MF numbers, if we look at 300 MF:
Shako, 300MF 8 players Andy 1:422, 1 players 1:771 (still a 1.8x difference in efficiency).
The difference in drop chances is substantial, especially for items off of normal monsters.