I presume that swapping ideologies, even if that were true, that Democrats could blame their past actions on someone else.

That is a cop out.

Lyndon Johnson said:

"I'll have those ni**ers voting Democrat for the next 200 years"

And Democrats still believe they own the Black people's vote. They believe Black people owe their vote to Democrats. It is in the Democrat's genes to own the black people and use them to their advantage just like their ancestors did.