My theory is that the reason the first warrant was denied was because it wouldn’t give the judge enough cover. He sent them back to get more supporting “documentation” so that he would be able to sign the warrant and then claim that he made an “honest” decision based on evidence only (and not on his desire to help Hitlery and sabotage Trump).
They then went back with a Yahoo News article and got the judge's consent.
Bingo. The FISA Court is a rubber stamp fraud to provide a fake veneer of a legal process. The reality is the FBI spies on whoever it wants to for any reason it wants to. You’re right. The judge’s inital rejection was strictly a CYA move.