The truth is that the upper middle class (today's equivalent of Democrats) wanted to enjoy the fruits of slavery too. Lincoln needed the support of the abolitionists (today's leftists) or he would have probably never gone to war.
They have to rehash the old shit because they stand in opposition to people trying to do anything new. Gay/trans rights for example. They've been regurgitating the same tired rhetoric since the 60s (and probably earlier than that in some form). Conservatives have to fall back on old strategies because doing anything different would be progress
It's a natural tendency for authoritarians to select individuals as representatives of movements. It's easier to slander individuals than ideas, and it aligns with their beliefs in heroes and villains.
I'm accusing you of cherry picking negative examples to reinforce your narrative. There is no confusing abolitionism if you have enough integrity to understand what the word means. It's easy to pick examples of people who lack integrity so that you can taint a movement with the sins of the individual. I can tell all I need to know about your beliefs from your tactics.