If you stand on one foot, you're easily pushed over. Stand on both, and someone can still knock you down. Get down on your knees and brace with one hand, and there's still a corner that caves. Balance on your hands and your knees, and it's much easier to stay steady.
Obviously, just grabbing random verses and throwing them together to make a 'doctrine' doesn't work, but when someone has one verse out of Leviticus to combat six verses from both the Old and New Testament that were interpreted properly, who do you think will be right in the end? Of course, 'Bible trumping' in an of itself is kind of a dumb phrase to use, but still mostly true... when used correctly. You can't base doctrine on one single verse.
The discussion then goes down to interpretation, which is where all the denominations come from.
