...because anyone who voluntarily chooses those terms and also supports the ban must be being inconsistent somehow...

If trees could get together and set a limit on how tall any one tree is allowed to get, they would be better off (by expending fewer resources on growing large trunks and more resources on reproducing), even though they're all individually better off violating any limit.

Robert H. Frank uses this idea to justify several types of labor regulations in his columns and books. I just want to point out the principle here and note that similar behaviors aren't necessarily irrational.