I see a number of "pro gun" memes where the basic subtext (for anyone who knows how to think) is: "I own a gun, and I would be proud to kill another human being." For example, "Kill 'em all, let God sort 'em out."
Really? Would you also be proud to beat your wife? To kick a dog? To steal food from the mouth of a child? To knife a soldier? To chainsaw a cheerleader? To tell God to "suck it"? Bet you would, you bloodthirsty murderer-wannabe.
I think the best meme to make my point is the one that went something like "Guns and God. Trespass and meet both of them." I think that person needs to add "And when you meet God, you can tell him I said 'Suck Your Sixth Commandment!' - because, that's what this little sign says, right up there for anyone who knows how to think.
I'm prepared to allow that this person doesn't really mean it, but just as actions speak louder than words, so words speak louder than intentions. But, in the case of a bumper sticker that says "Screw the Sixth Commandment," (by any other words) actions have already spoken: bumper stickers don't put themselves on bumpers. Someone bought that sticker, carried it home, stuck it on that bumper, and left it there, to show the entire world how proud that person is to say "Suck it God, I own a gun."