Given the current geopolitical situation, and the poor state of readiness in the military, I think might have felt he had to go along to get the military spending increases he needed. Recall that the military got sucked into the sequester situation and never recovered.
I get your point, but still trying to understand the immediacy to pass and sign this monstrous bill that no one Congress-critter had time to read and debate. Seems we are relying on their staff/lawyers to write our laws.
Does no one recall Pelosi's middle-night passage of Obamacare that took over a 6th of our economy? Is it just me that remembers her fateful words, "We have to pass it, to see what's in it"?
President Trump did the same thing with this 2000 plus page bill. He, McConnell, Ryan could have insisted on more time for their staff to read the bill. But no, they had to go on Easter break.
Potus, alone, could have insisted study time on such a complicated bill. I think he has 2 weeks before it becomes law without his signature. He could have then lined out the parts he thought wrong with MAGA, with a threat of a Veto and sent it back to the House.
So the Fedgov shuts down for a short time. Again, so what?
Is there a war coming? That's the only reason I can see why he signed this atrocious legislation.
I made this point on another thread. Few reslise the hollow state of the US armed forces.