I don't think anyone claims that Pogacar is crash immune. But it's definitely worth noticing that he is one of the best bike handlers amongst the GC-riders which should give him a better chance to get through a Grand Tour.
Good bike handling in my book is also about going fast, in all scenarios.
Take descents for example, i.e. you can see riders like Pierre Latour totally blocked mentally & not manage. It's like a complete shutdown & they can no longer do the job. That's a serious handicap for a GC rider.
Roglic though is a super fast descender. Yeah he can crash, but as long as he has the speed he can win. For example Jacky Durand on French Eurosport was screaming at him about his bad descending in the Vuelta, but the clock told a different story.
At this point I assume crashes is the next element on the list of "perceived Roglic weaknesses" to be checked off, i.e. after the mythical "bad third week" was put to bed in this most recent Vuelta, I say the "Roglic always crashes" narrative is next. He'll ride a GT next year without crashes or incidents & then everyone can get to talking about the next "weakness" (which is probably going to be his age, sooner or later).