re: why do all African Americans defend each other?

I would not say "all" but maybe a "perceived majority"

Plenty of blacks on facebook that call it like it is "Wrong"

but yes, what we see on TV at times are black people rioting and defending other black people who they do not know personally, nor do they know the facts about why that person ended up "Dead". That doesn't seem to be a priority...Defend and protest!!! without facts

craziest phenomenon I've seen because that makes no sense to me, --a white person.

For blacks it must be some kind of relatable bond from daily societal injustices..?

I have no clue, ask BHP