Dianne Feinstein is old. This will most likely be her last Senate term. Gun control has been her personal crusade since she's been in politics. She's looking for a legacy and wants her legacy as a Senator to have been banning assault rifles --whatever the cost to the rest of the Democrat agenda.
I thought her legacy was passing millions of acres of Death Valley into a ‘monument’ where no recreation can still happen.
She engineered that, and thousands of people are still mad about it.