Community is not a claim that a large group is correct simply because it is large. Sound cooperation includes truth, fairness, sincere counsel, and consultation. Collective organization never excuses injustice.
For example, students who coordinate the care of a classroom or library can accomplish more together. But a group that agrees to bully another student does not turn wrongdoing into good simply through agreement.
عَلَى الْجَمَاعَةِ is not merely a statement about standing physically together: in context it carries the message of divine support for the community.