CC -- that's a lovely strawman you built, but no one in this thread has said "IDPA serves no benefit."
This discussion is about the use of humanoid targets -- ones that are even more realistic looking than normal IDPA targets -- as score-neutral "bystanders" that you were not just allowed to shoot indiscriminately but were actually encouraged to shoot by the stage design.
"IDPA teaches people to shoot better" is a complete non-sequitur.