For one thing, it's the timing. The race for 2020 is getting into gear and suddenly NOW dems are talking "reparations for black people" (something we never even heard a peep about during Obama's whole presidency) and paying off student loans.
On top of which, those are for /targeted/ demographics, and "coincidentally" enough, the same demographics Dems have been bleeding recently. Generation Z students have been showing a swing back to the right, or at least away from the left, as have black people, in the form of Blexit.
As for "tax cuts", those promises don't target individual groups, they're blanket promises at least /claimed/ to be for everyone. And you know what? Promising tax cuts is a time-honored tradition as old as the hills among politicians running for any office, of course it's intended to get votes, it always has been. It's not like Trump invented that particular election promise. At least he actually delivered on the promise last time around.