Didn't Whitebeard say that after One Piece was found, the entire world would be engulfed in a war?
I'd say it's something which states the absolute truth, which would be the Rio Poneglyph. Luffy is the kind of person who would get pissed off at what the WG had done in the past, if it's absolutely unforgiveable. Would be a good point to go to war.
Just my 2 cents.