"It can be done. But can doesn't mean should." I'm getting worn out on this turn of phrase. Yes, can doesn't mean should. But also, couldn't doesn't mean should

"It can be done. But can doesn't mean should." I'm getting worn out on this turn of phrase. Yes, can doesn't mean should. But also, couldn't doesn't mean shouldn't. You have to justify "shouldn't". TFA does go on to justify it, which is appreciated.