Why would a vote be very polar? Why should I vote against GMC if it has no bearing on something.
This is not a race. You are misinterpreting this. There are 2 problematic aspects:
Pollution:
Pollution is very difficult to control. If someone just spawns a T8 Rocket in and starts it, then they usually don't care about the side effects. Pollution spreads over to other Chunks, you should know that when you have already reached the moon There have been a couple of cases where someone has spawned T8 Rockets and created massive amounts of pollution. This is then skipped over to another player and his complete Base was "devastated".
Parallel Ticking:
In GTNH, the tick rate determines the speed of the machines. The tick rate is getting lower the more TEs are running at the same time. Since many GMC players want to build a relatively complex base and also build complex systems and processing arrays there, they only promote the slowing down of the tick rate. At a Tickrate from 1:4 ( 1 Second ingame takes 4 seconds in RL) nobody wants to play there anymore. In Midgame you have to wait several hours for materials to be processed. I personally don't want to wait 4h for a Material that should only take 1h to process. Of course, every normal player does that, but the difference is that a GMC player spawns everything in a split second. Of course, that won't fix the problem, but we will delay the problem from Days to Months.
You are also welcome to visit other GTNH servers. I am sure that hardly anyone gives out GMC for a good reason. GMC is not intended for this modpack. It destroys the sense of the game.