Configs?
They can disable GT's modifications.
So I have a point, you "configs? What is that black magic?" dumbass...
Oh, Right, Ok. I'm dealing with stupidity, i must put on the baby gloves.
You see, There are lots of places where people connect to called servers.
On these servers, they typically just play the standard default modpack because getting people to deal with configs is to much of a pain. And since FTB decided that Gregtech should be in full intrusive mode (Instead of the promised not as intrusive configs) Most servers will STAY on the default configs.
Now also due to the fact that most people tend to want to play with others, these base configs are what most are playing with. And as far as I'm aware, you aren't able to just use your own configs over the servers. That'd be "Unbalanced".
Now if you like to play alone, whatever, but your config solution does'nt mean jack to the majority of people who play the modpacks, and you should'nt be expecting everyone to play forever alone as you do.