According to a discussion I just listened to on YouTube, Akira Toriyama stated in an interview shortly after DBZ ended that he was upset and disappointed with the portrayal of Goku in the anime. According to Toriyama, he never intended for Goku to be a righteous hero. Toriyama intended for Goku to be a selfish and self-centered man who really only cared about fighting. Goku does not primarily fight for others, he fights mostly for his own enjoyment. The reason he does so many questionable things throughout the series and endangers the lives of his friends and family is because he puts himself before them. Goku, or the manga portrayal of him at least, was never meant to be a good person nor a role model.
What do you think about this? I think it explains a lot and also shows just how different Goku is from most protagonists.
I also will take this into account while writing my upcoming fan fiction. Cyborg Gohan, the protagonist of my story, fights only to protect himself and others. He doesn't enjoy fighting and isn't even a warrior at heart. This makes him the complete polar opposite of his father and in the end makes him the better hero.
-Racob has spoken