What makes you think those are the songs they want to play, or they aren't doing whatever they please right now? I agree with what you are saying, and would like to hear all those BUT I think U2 has always been about getting the biggest reaction and pleasing the largest number of people. I think they would quickly go away from a lot of that stuff (if they ever played it) because they wouldn't get the huge reactions. All the comments about not playing drowning man were because they were so worried about the reaction to it, and it would kill momentum (ie- crowd won't go crazy over it).
I think that is why they are still playing elevation almost every night. They cannot think its one of their best songs, but they get a huge reaction. Maybe I'm wrong but I think they enjoy playing the songs that get the biggest reactions, and would explain a lot about their song choices.
I am not saying that they are not doing what they please. By in large, I think that they are. Otherwise, we would not have 7 new songs with UV, UF, YBR and ES played as well. Though I can not know their minds or hearts, they are playing new material and what they feel goes best with it.
I agree with what you say about the crowd reactions. I have never been in favor of completely eliminating popular/well known songs from the set, just rotating them and maybe not playing ALL of them in one night. Like others, I understand the drowning man momentum argument, but then they go and play YBR? I like it, but it loses 99%. At least UF is well known and UV is an upbeat, amazing track, both accompanied by great visual effects.
Songs like MOFO, Please and LNOE are powerful enough to overcome the "WTF" effect, in my opinion.
I think its a combination of reactions and what they feel like playing. In playing UV, they are trusting the audience to respond to a great performance of a great song, even if they may not know it that well.