First if you can recall, the democratic party created the KKK, but today they perpetuate BLM, race baiting, defunding police, ( yes they seriously suggest defunding the police and some democratic states already have, with the intent to abolish police ) needless to say the democratic party take the chaos and include it in their policies only to gain favor and obtain power.
You bring up this conflation a lot.
Despite having the same name, the Dems of history are not the Dems of now. Left and Right wing names basically traded hands in American history.
Democratic party will not do anything for black people, and never have. The list of broken promises go on and on.
They've done quite a lot, and seeing as the Left appeals to a victimhood mindset it makes sense that they'd appeal to minority demographics racially just as they would for their ideas of classism and ableism.
Progressive views want to profit off of changes while Conservative ones only yield counter-cultural values once the culture deviates from where it once was historically, so of course a party of change would represent the disenfranchised (whether they actually believe in their plight or not). It's about the same as expecting religious lip-service from the Right.
The only things to serve as an exception for progressive views are things like Unions vs Modern Tech, such as the self-driving car being slowed down so that human drivers have longer to work. Leftist union practices and Right wing fear of change can agree on how Technology shouldn't be "going too fast".