Everyone builds their identity in relationship to the groups around them, it’s impossible to do otherwise. Nations, states, cities, schools, social cliques, sports teams, groups based around hobbies and interests, etc.…You establish who and what you are by which of those groups you support or oppose (however fanatically or apathetically). You can no more be free of all groups’ influence than you can be free of the gravity of the sun and the moon.
Not hanging your identity on an association with any particular group (family, religion, political parties, sports teams, academic groups, whatever) let’s your self-esteem fall down the stairs without any hand-holds to catch on the way down. People use their affiliation with groups to draw strength and bolster their self-image. When everything falls apart around you, what are the cornerstones you use to rebuild your life? The values you’ve taken from the groups around you and woven into your identity.
Yeah, this can be taken to unhealthy extremes, just look at all the self-important hyper-partisans calcified into their views in defiance of logic and fact. But the other end of the spectrum is feeling an apathetic blah towards everything (yourself included!). Wouldn’t want to over-correct when trying to avoid their negative example, now would you?
Me? I’m ****ed up in the head with an Avoidant Personality Disorder. I avoid people (duh) out of anxiety and shyness, which naturally leads to weakened bonds of affiliation. Yes, I (like any other human) need to belong with others; not belonging is a mark of vulnerability and weakness.