He had Beric explain his loss of memory and how each time he came he felt like he was missing a piece of himself. And then he went one step further with Lady Stoneheart to hammer home that their changes run so deep that they are now different people. Same with The Mountain becoming Robert Strong.
I thought the combination of personality and name changes cemented the idea that death and resurrection create a fundamental change.
Except everyone who is resurrected still seems to recollect who their allegiance is to, who their enemies are and their mission.
Man, coming back from the dead would change you regardless. I'm happy to accept that. I'm not accepting that the magic was the cause of the change.