You do realize that the government had already enacted rescue plans as much as possible. There was no airport to speak of, no safe docking facilities, and no way to move supplies from the main land to PR via truck. Couple this with the complete destruction of the power grid and you can see anyone's hands would be tied.
The military has troops trained for setting up airports, rebuilding power grids, using heavy machinery to clear and repair roads, and so on. Country (re)building is one of their missions, though not their primary one. They had been planning a response long before Maria hit;
HOWEVER
No matter what DoD's plans were, and how many resources were staged and ready, they cannot move in unless the president legally starts the process.
By day 11 after Katrina, there were 78,000 troops working to repair and support the area.
By day 9 after Maria there were 5,000 in the area (the 10,000 in news stories is on day 11 and includes more than soldiers - but it's still just 1/8 of the manpower in PR.
This series of tweets (attached) from 9/25 is true. I verified this by a trusted source. The WH had.no.plan. But all of the supporting organizations did - they could not do anything without WH direction. Things are moving now - but they weren't on the 25th other than a few relatively small resources.
To respond to the OP - I have no idea what it will take for Trump supporters at large to admit that he's a mistake. I can't figure out how he hasn't crossed that line so many times already.