According to the Constitution, spending decisions are for the House of Representatives. The Democratic message is that Republicans are a deranged minority. Nevertheless, the most recent congressional elections put Republicans in the majority of the House and the Democrats are the minority. They also expected the House to cave in to the Senate intransigence, as they frequently, but not always, have done in the past, for "the good of the country" and to support comity.
Now, the President wants the House to have a vote on a spending bill, as if they've been on strike or something. (He yelped that disgruntled workers who disagreed with their corporate employer and didn't do as they were told would be fired). But the House has passed and sent four separate spending bills to the Senate where they've been voted down and the President declared he'd veto them even if passed.
Great theater, guys. Take a bow, and exit. Stage right.