People under torture will say anything and everything to get the torture to stop. Most of what they say is what they think the torturers want to hear. And most of it is lies.
Not focusing fully on a single individiual in terms of their threat to the United States is not the same as "giving up on them".
Let me inform you a bit about intelligence gathering, since you appear to be completely ignorant of it. It is not a situation where you recieve a piece of information and then bust in commando style like some movie. Various strands of intelligence are gathered over significant amount of time from various sources. As strands begin to be discovered in a repeating fashion then interrogation can be steered towards expanding upon those and the information can be floated past higher importance detainee's to see what comes up. Information is build upon layer by layer, with multiple verifications and redundancies in hopes of assuring that no action is being done on bad or faulty intel.
That's just mostly from interrogations, and not even getting into gathering the information from assets, ground intel, survellance, raids, etc. It all plays into it.
Bush likely didn't act in 2004 or 2006 because the intel was still loose, still in its infantile stages of being worked into the string that eventually brought him down. Something like an allias that comes up repeatedly that leads to another allias that leads to a connection to someone which leads to another connection which leads to a name for the first allias and so on and so forth, building and checking and verifying things.
Bush doesn't deserve all the credit, and to that extent neither does Obama. Most goes to the men and women of our intelligence fields and the military. But whatever credit you are going to give to Presidents for making this happen, it has to go to Bush as well as Obama...not just one of the other...because itw as the policies, actions, and men put in power by both that eventually led to this capture.
"I am appalled that somebody who is the nominee...would take that kind of position"
"A court took away a presidency"
"...the brother of a man running for president was the governor of the state..."
It's horrifying because Trump is blunt instead of making overt implications.