User blog comment:D.Dragon123/Why does Dragon hate the WG?/@comment-3986064-20110725090259

He hates the WG because he knows what happened to the ancient kingdom from Roger, then at his execution, he decided that he will become a revolutionary and change the world by overthrowing the WG.

Also he hates the WG because they killed his brother in law(I say that his wife is the little sister of Roger, explains why Luffy looks so much like him right?) now for his wife, that's where I can't think of anything more.

So Roger told him about what the WG did and why the ancient kingdom went to such measures as creating superweapons, those used to stop the WG, but it was too late, the war was being lost, they left their knowledge in the Poneglyphs, which Roger knew how to read, he heard their voice so he knew the truth too, but his disease stopped him from doing anything.

Oh yeah, another reason is because he has the will of the D, everyone who has it ends up against the WG at some point, only Garp had enough self control to be a marine, but in the war, if Sengoku didn't keep him down, then bye bye Akainu, and bye bye position with the marines(WG organization)

This was all speculation, do not think that this is what really happened, its just my imagination gone wild by creating possibilities with all these dots