I dismiss the whole thing as "just anime things", but to find the above intellectually acceptable (for lack of better words), you'd have to accept 2 things:

1) That Inosuke can move all his vital organs, and

2) That Inosuke had time to do so.


(1) is take-it-or-leave-it, not much to discuss there since it's BS anyway. (2) depends on presentation. Inosuke was clearly ambushed here and showed no resistance or evasion towards the sickle at all. To think that he moved his organs in response to this attack is a bit of an asspull. To me, something like "I locate my organs elsewhere at baseline for exactly these scenarios" or "I'm born with my heart in my abdomen" would at least be consistent.

What they could have done was have Inosuke's spidey-sense trigger just as the attack hit. At least then we can believe that he reacted to the hit, even if he didn't show any signs of dodging.