In any movement, as soon as someone actually goes out and tries to do anything, that's when the hating and infighting will start. Up to that point, conflicts are more latent because we can more easily just ignore our differences. When you start to become more prominent and do stuff that gets talked about, that provokes people to criticize.
It's easy to get a group of people to agree, "We'll take no action" because that's simple and involves no risk. As soon as someone decides, "It's time to take action" then people disagree on exactly what action to take, and how.