"Why would UFOs act so weird and sometimes crash?" is not a strong objection.

An objection I've repeatedly seen is that UFOs can't be advanced ET because they do nonsensical things like: Are somewhat visible, yet don't openly contact everyone. Fly around in big, noticeable craft instead of using nanomachines, invisible vehicles, etc. Are extremely advanced, yet still periodically crash All these objections rely on predicting what an "alien" civilization would be like, which is almost definitionally impossible for anything truly "alien." What's more, we know acting like...