False equivelences aside
So the big argument being fought is over the false equivelence of metaphors that reference violence but have been drained of actual violent connotation (i.e. you're dead to me, don't bring a knife to a gunfight) and those that validate violence as an acceptable solution to political disagreement (inviting donors to shoot targets with political opponents names on them).
I am not going to waid into that debate because plenty of other people have and because I don't believe it's being had in good faith; in otherwords Sarah Palin wants to be able to say whatever she wants without being held accountable and it wouldn't matter how direct the connection is.
While I don't accept that all metephors that spring from violent imagery are the same I do think, in general, the use of violent and sports imagery does have negative impacts. Specifically, there's ample evidence that rampant use sports metaphors in politics desensitizes people to the actual, real life impact of policy.