Even a show like South Park has been known to draw its comedy from the well of conservative (if not hyper-conservative) impulses.
On the anti-gun-control side of the joke war, things aren't quite as simple. Though, it seems that the general modus operandi tends to be an appeal to historic patriotism (particularly in terms of the revolution) or fear (most notably the tried and true Obama is Hitler/Stalin/Mao/Che/etc.).
Like it or not, each of these examples is funny. Maybe not to you, but they are funny to someone. What I find so interesting about these particular jokes is that the teller points to a truth that orients her or his humor. Because the funniest jokes are the ones that contain at least a modicum of truth and tend to work as reductions toward that truth, looking to joke wars might be especially useful in determining the specific points of antagonism between opposing sides.