Jesus, where did you grow up. Where I grew up we would make the first part of the joke but not the second. You are going to jail. Not "you are going to get shot in the head". Dogs biting dicks off?! America is too puritanical for that kind of imagery to fly.
Yeah, I should have guessed it sounds too much for fellow Americans. I'm sorry.
I grew up in Asia. I guess it's one of those cultural differences, like calling people "fatass" or drinking on the street without a shirt is not too inappropriate in some places. So people would have to shrug it off, try to adapt, and try to think those are just jokes without bad intentions. But still, it hurts and it does have life-long negative impacts on many people as far as I can see.
On top of that, I find people from better-educated families, or people from many other provinces in the same country don't share the same experience as us. My guess is economic and education status helps. From what I can see, the current generation of kids does receive substantially less abuse than say three decades ago.