He's staunchly against guns, and if you re-read the book you should notice his stance that guns in the home are a detriment to the safety of your children.
I work in Corporate Security and we use GDB sometimes, especially to evaluate potential stalkers and any other threat that might boil down to some sort of psychosis or major mental defect. Ultimately, his recommendations always include to pay his company to protect us, because its not possible to protect yourself. It's a nice touch we're rather fond of.
If you really want to read an anti gun rant, pick up his other book, protecting the gift. He regurgitates his first book and adds anti gun hysteria inducing rhetoric.
Don't get me wrong, this is a good book to own because he's dead on in regards to how to assess most threats. You'd have to pick up three or four other books in order to cover as many bases as he does.