can you come up with a valid argument as to why people should have violent dogs?

i can't.

at least with guns, there's a human on the other side. you can make arguments about how gun control isn't the answer, so much as a change in the culture is. and, that remains true with dogs as well - the real answer is that we need a cultural shift away from the machismo that glorifies the ownership of these breeds. sure.

but, a violent dog doesn't have a safety on it. you can't lock it in a cabinet, where the kids can't get at it. it's an omnipresent danger, with it's own personality.

i don't know exactly how you do this, and i would like to ensure that the science is consulted - because i want it to be effective. if the science says it's not going to work, what's the point, right? but i would like to see stronger action taken, nonetheless.