That's a feature, not a bug.
As long as a human has to drive, might as well train him to do so correctly.
I think you are missing the original person's point. It's not that they don't use turn signals; they are probably like myself who doesn't choose to activate their turn signal until they know it's clear to change lanes. This is a courtesy to other drivers as the driver in the lane next to me doesn't have to worry about will they/won't they if my turn signal is activated while the lane is NOT clear.