Most people, especially in these recent times of highly charged political rhetoric and internet trolling, cling to their beliefs like someone protecting their junk. Friendships and families are discarded to reinforce our fealty to core beliefs. The concept of 'identity politics' is no longer limited to race or gender but has expanded to Progressive and Conservative, religious affiliation and whether you prefer Apple or Android.
The biggest problem with this phenomenon is that our beliefs tend to change over time (both experience and information adding and adapting our world views) and are often - and I mean almost always - wrong. Tying your concept of 'self' to these external factors, no matter how dearly held, results in the cementing of self concept and a rigid inability to work within society.
You are going to be wrong a lot as you travel through life. Most of the time. Your ability to succeed and progress forward is in direct proportion to your willingness to bend and change your beliefs based on your own ignorance and your own mistakes.
You are not your job.
You are not your skin color.
You are not your gender.
You are not your religious affiliation.
You are not who you were ten years ago and you won't be who you are now ten years hence.
You are the lessons you learn, the acts that you do and what music you like. Everybody knows that.