No one is arguing for individualist isolationism (at least I am not) but individualism is not that. If you just reject individualism from the get go, you are also willing to let an individual's freedom to do as he pleases slip away as well.
Most individuals realize that working together can be beneficial at times and as such they would likely work together. I just want them to be able to make that decision, not have some collectivist organization force it upon them. Furthermore, collectivist ideas tend to group people based on race, sex, color, intelligence, wealth, etc. and in the process people's individuality is often forgotten as well.