People in Naruto world cannot fly without getting any logical help. Even though, the realism standard is different than what we consider in real life, the standard in the naruto world should still make us perceive that difference (since, there is still a level of realism in the naruto world.). My reasons are still valid - controlling the snakes and the ability of the final form. There is significant difference between wings that is created for the purpose of being a wing, and a structureless thing that is created to replace it. But, I still consider what I said before as ok. Yes, it seems, the connection part of the wing to the body is still there. Chiyo was one of the oldest person we have seen, she had fought Uchiha in the past but like the other she rathe came with a way weaken the danger of the Genjutsu by avoiding it/distract the user so you cancel the Genjutsu by yourself, Gai decided to avoid the glance completely, Haku came with sealing both the fighters's sigh.Дeciding to negate the sight power by directly looking at it isn't that obvious, in fact it's incredibly reckless.Deidara might have passed a decade honing this skill in order to kill Itachi, I wouldn't assume it's even possible for anyone anyway. You assume our knowledge as readers are shared in the Narutoworld, Zabuza knew about the Uchiha, the Sharingan and Kakashi but he had not clue about the danger of the its Genjutsu. At least, that is what I understand, otherwise, praising what Deidara did would be unnecessary. He said resisting sharingan, and a possible meaning for that is to stop sharingan's genjutsu before it has any effect on the person.

The amount Deidara experienced is not something that cannot be thought of even if the person hasn't experienced it himself.ДЄnd, lastly, what Deidara achieved, based on his words, is different than dispelling genjutsu of sharingan. It is knowing the genjutsu effect of sharingan and developing an ability to counter it. And, secondly, it is not only seeing and losing to sharingan and living through it.

The second reason, I don't think as valid, since number of ninjas that had lived through sharingan shouldn't be that low, considering the possible number of generations.

The first reason can be considered as valid (mainly because we don't know exactly how much time he spent on his training).

Kowai iina kancolle