He doesn't believe that it's worthy of his time, he chose the Citadel because that links to more universes meaning if the Citadel goes down then all universal transportation goes down as well
Ay Johnny I'm gonna give you a staff so you can help me. Wow. Thank you!! You're welcome. Now let's go kick Beldum's butt to the next universe! *poof*; Right behind us. Redi? Where's the army? CHAAARGE! *pew pew pew*; *ZMMMMMMMM*; *KABOOM*; All of that for a drop of blood. *CRACK*; We need a miracle to defeat him Redi! To be Continued