You know.  After reading a some more articles on the decision I am left wondering if this is just Trump's style of fomenting division in his underlings that he's trying to carry out in Congress.  It could be something simple like Trump wanting to keep the budget issue simple to clear the dockets for bigger issues like tax reform or even possibly to create breathing space for emergency funding in anticipation of Hurricane Irma.  But I don't feel Trump is crafty enough, or even trusting enough, to form such a plan.  I'm more inclined to believe he's carrying out his past threat during the ACA repeal fiasco of "I'll have to work with the Democrats" because I certainly don't see Trump, or even the visibility of Trump's actions, as working to "bridge the divide."  Especially after lashing out repeatedly and at length at Sen. McConnell.
This wasn't really a very big decision nor is its impact that severe.  Yes, it draws blood but the hit on the Republican party leadership is shallow.