When you join a large firm, you are joining the team.
I asked a US Marine who he was loyal to, and he said his unit. Not his country or the military.
The same happens at schools and universities: you might know your classmates on your course, but you don't know all the people at a university.
Same goes if you're a sports fan. You might be a supporter, but your experience depends a lot on who you're sat with. Ultras, those kinds of hardcore groups are rarely huge mobs.