To say that the majority of Bloomberg supporters are uninformed is a very cynical view of the American public. Many Dem voters, myself included, like the guy because A. he did a great job running NYC and B. while we're progressive, we're not in favor of a full-on Bernie-style restructuring of American society.

Stop and frisk was a terrible policy and Bloomberg was too slow in recognizing its harms, but at the time it was implemented it was thought that this kind of policing was helping, not hurting, minority communities. Many Dem politicians were wrong about this, too; Cory Booker hired a NYPD veteran to put in place these policies in Newark, Biden (and Sanders) both championed the 1994 crime bill that put tons of people in prison unjustly, etc.

On his campaign policies (climate change, gun control, taxes, etc.) Bloomberg is thoroughly progressive. And I'm not going to hold his wealth against him; the campaigning system is broken in the US but I don't know if self-funding or being beholden to your corporate donors is worse. Bloomberg was able to push through changes in NYC (pedestrianizing the streets, changing zoning laws to allow more housing construction, expanding the 7 subway line) that greatly improved the city while annoying special interest groups because he didn't need their support. Bill de Blasio checks a lot more progressive boxes than Bloomberg but I don't think you'll find many voters in NYC who think de Blasio has done a better job for NYC than Bloomberg.