It's a shitty stupid system but the sense of it is exactly what you said.
To make sure that combat doesn't end on turn 1 because everything is knocked down or polymophed etc.
A much much better idea would have been to simply return to D:OS1 system which was better in every conceivable way and allowed you to resist such stupidities through stats, but whatever. I think they were trying to make stats as useless as possible this time.
But I do agree this new system.
Why should I take the control effect when I defense well?
If enemy doesn't break my defence( or armour), then I could resist thier control.
Is it really that hard to be understood?