Well the fact that torilian gods are almost universally tyrannical forces that are a malus upon civilization from the mortal perspective probably gets a few people into the wall each generation.
I mentioned this earlier, even the 'good' gods are basically toying with mortals, largely to sate their own agendas and egos.
That's not true. Certain gods actually go out of their way to help their followers. I don't like many gods, and I certainly don't like the Wall, but there are Torilian gods who really care about people (deities like Ilmater or Eilistraee are known to be very compassionate and to directly help people in need in various ways, for example, even when they're not followers). The Wall is a fairly recent work of Myrkul in the setting, not some kind of universal rule that has always existed as a device for the gods to keep exploiting people or something along those lines (so I hardly believe that things are like you are trying to portray. FR is not an "all gods are a******s" kind of setting, though many actually are).
Also, IIRC, correct me if I'm wrong, when Kelemvor destroyed the wall the other gods weren't trying to get it back up. Kel restored the wall only because in the novel the authors decided that people would suddenly take suicide missions for good causes just because the Wall wasn't there anymore and Kelemvor had offered a good afterlife to people who did good (and this situation is clearly BS). I even doubt that the Wall is something that the deities could influence without holding the portfolio of the dead.