I get the appeal of having a woman on our money, but why get rid of Hamilton? He was a crucial figure in the early years of our government. He opposed slavery, was the first Treasury Secretary, and fought to ratify the Constitution.
The $10 was just the next bill up for redesign at the time this campaign materialized. I don't think the proponents ever had any anti-Hamilton agenda.
And as awful as Jackson was, I see no reason to remove him from the $20 bill.
Well if you want to put a woman on existing currency,
someone kind of has to get bumped off, and Andrew Jackson's ghost is the one who will be least bothered by the change. Also, as you point out, he was indeed awful.
