Why do people get defensive when given feedback?

I think the phenomenon has its roots in "I cannot be wrong" mindset

If you think I am wrong - you have misunderstood me, so let me explain (this is where the defensive argument comes in)

This is probably due to the social penalty placed in early childhood where wrong answers get you bad grades or being ridiculed/punished under various social settings for being wrong

...so the stigma of being wrong stays with us for a long time due to the early conditioning

Unfortunately, there is no easy fix for this...it takes a long journey and a lot of learning for you to know that you don't know much!

but you only know that after a lot of investment in effort!

Some young people have the "gift" of simply trusting someone to know better than them, while retaining the ability to be an independent thinker. This is rare.

In my experience

a good number of early career folks: I cannot be wrong mindset

some early career folks: I want to be successful like her/him, so let me follow what they say

about half of mid career: I need to know my blind spots to advance, so let me get as much feedback and hear it out

majority of successful advanced career: in constant feedback mode!

"Ignorance more frequently begets confidence than does knowledge" … says Darwin in The Descent of Man