Kruge explicitly says he wants Genesis as "the secret of ultimate power!" Later he says "I've come a long way for the power of Genesis." It's obvious that he wants to claim the weapon for his own use. This is also a guy who blew up his own lover because she saw the blueprints, and who disintegrated his own gunner for making a mistake. It's incredibly disingenuous to suggest he was only motivated by self-defense. His invocations of "galactic peace" are obviously meant to be interpreted as propaganda and hypocrisy.
I mean, let's face it, as fun as Lloyd's performance was, Kruge was one of the most exaggeratedly, blatantly Evil characters in the Trek franchise. He killed people on a whim, tortured people, murdered Kirk's son to make a point, and said it was exhilarating to be on a dying planet. He stopped just short of literally twirling his mustache. The movie went to great lengths to demonstrate that this was a villain so heinous and irredeemable that even James T. Kirk, the man who chose to seek peace with the Horta and the Gorn despite the violence they inflicted, was driven to the point of saying "I have had enough of you" and kicking him into a chasm (though he did at least offer his hand first). Kruge is no more the good guy than Hans Gruber was.
