Why do gang now days go against each other?

About Me

Hi my name is Amya, and I'm 14 years old; my birthday is coming up on May 23. The question I asked is why do gangs go against each other now days? The reason why I chose this question is because it really shouldn't be black on black crime all the time, and white cops are killing young black men now. You should be entrusted in my question because back in the day they protect now the killing each other you should wonder why it all changed.