I really doubt that white men who own baseball are actively working to prevent Blacks from playing in MLB.
That may have been the case as recently as, say, the seventies. I'm not sure.
But the Yawkeys of baseball are pretty much gone.
I suspect that money is what it comes down to. If a player can make a team money than he gets a chance to play.
I'm sure that racism still exist in baseball, just as it does everywhere else. Who was that dumb old f*** from the Dodgers that said something like "yur coloreds can't
manage" blah blah blah? Those type are still in the game but have learned to keep their mouths shut so they can still make money.
There are socioeconomic reasons that there are not a lot of Blacks in baseball. I'm not sure that racism is a big factor at this point.