User blog comment:IamJakuhoRaikoben/Chapter 412: Dance Unto Ishgar, Review./@comment-7418318-20141208143333/@comment-25111584-20141208144517


 * 1) Gray knows that Igneel couldn't defeat E.N.D.
 * 2) Gray does not know that Igneel told Natsu that the book shouldn't be destroyed. All Natsu has told him that 'he made a promise with Igneel', not the best of reasons to keep the book intact.
 * 3) Gray knows Igneel doesn't know anything about Silver, what he might have told Gray about destroying the book. Silver was a Devil Slayer, after all.

He also has no reason to trust Igneel. The only things he knows about Igneel are:
 * 1) He is a Dragon. So were the ones which ran rampant during GMG, including Igneel's friend, Atlas, who turned on Rogue only because Natsu was Igneel's son, not for the sake of humans.
 * 2) Igneel made Natsu suffer for some reason which hasn't been explained yet.

I'm certain that Gray won't be able to destroy the book and his actions will make things difficult to E.N.D.. But, from the info that he has, I don't see how he is being stupid ... His decision is perfectly reasonable.