Edo itachi halves the damage of the 1st two pure ninjutsu attacks (standard or mistery).

Your resistance may be off the charts but that means nothing against taijutsu attacks (pure tai or even the ones combined, tai and nin).

There are a lot less ninjas or methods that buff your defensive than your resistance, thus your defensive tends to be way lower than your res during the fights.

Also, not trying to be mean, but aren't you guys tired of complaining about what u get for free and what you do not get for free? It's never right with you guys....you complain that you do not get ninjas for free and then after you get a ninja for free you start complaining about which ninja is for free (don't you think that's like being a bit spoiled?).