Saying "slavery happened to everyone at one point in history" denies the demographic-social effect that having slavery and segregation affect a VISUALLY DISTINCT people, so close in history, has.
Glad near-history didn't get in the way of Irish, Italian and Japanese Americans who were, in each case, treated like dirt outside their own communities.
Here's another fact of American history that bears pointing out: Hundreds of thousands of Americans suffered and died in one of the world's bloodiest wars in order to end slavery as it existed at the time. And, I'm not talking about rebels who repudiated the US government and supported the mid-19th century rebellion. The patriots who suffered and died to end slavery were supported by untold millions of additional patriots whose tax dollars and real goods were fully put to the cause.
And today what do we find being talked about as an excuse? Slavery. Guess what? Patriotic Americans died to give blacks a better opportunity in life. Make something of this gift that people of other nations did not for the most part bother to do for its populace. If the black community wants relief from crime and all it does to reduce its culture then start by DOING SOMETHING ABOUT IT inside your own community. Do not tolerate poor behavior. Report criminals. PUBLICALLY announce that is what is going to be done and then DO IT. If enough blacks do this then crime and all that comes with it will be significantly reduced within that community. Othewise little will change because non-black communities are working on their own problems and other communities' problems (including the black community) will be treated secondarily.