Well now you're unearthing a much larger reason Trump won. Call him anything you want - short-sighted, stupid, petty - he's not politically ambiguous. Empty promises get people out to vote, being fickle or moderate pleases none of your constituents. Especially not the minority caucus the democrats typically tap into.
Harris wasn't wrong for taking the high road, and the ACLU isn't wrong for publishing the dossier. The entire DNC is to blame for picking someone who can't make the promises their voters traditionally want to hear.