"<snip>...2 big biker types from up the road...<snip>"
Hey! Leave me and my buddy out of this......I'm actually a bit offended at this stereotype.....
For the sake of argument, we'll say your bikers are 1%er wannabe, Budweiser-drinkin', trailer-livin', Ford 4x4 drivin', drug pushin', welfare takin', sister's-name-on-the-water-tower, white-trash who have a reputation of having spent time in jail...........
Actually, most hard-core biker types I know usually carry at LEAST a knife, and quite often a gun, so I'd keep that in consideration in this scenerio. If one of them is grabbing a bat, they are not inclined to kill, just injure, but I'd be leery of one carrying a more potent weapon (then again, with a really good swing of a bat to the head, I'd probably prefer to be stabbed). I've also never known any of them to get into an altercation without cause. They get stereotyped enough, and get into enough trouble with the cops for "looking" a certain way, that they try to keep a low profile....usually. I know a few Hell's Angels and Outlaw members, and, unless they are doing a club function, you'd never know that they were "bikers". They downplay the "look". One of them wears bright colored and Hawaiian-type shirts. Anyway, I'd figure your buddy/family member is hanging with the wrong crowd and doing things he shouldn't, in which case, I'm going to decrease my association with him after this. If I'd read something like what you wrote in the local newspaper, I'd figure that the writer was biased against "bikers" and left out the fact that they were provoked in some way.........
Anyway, but to answer your question, I'd figure your friend or relative had a previous encounter with these guys and it has come to this. I usually can diffuse a situation before it gets out of hand (even if I have to apologize or say I'm wrong when I feel that I am in the right and have nothing to apologize for), but if it escalated to that point where one is hitting my friend/buddy and the other is grabbing a bat, and words weren't making the situation any better, I'd pull my gun and be VERY prepared to use it, putting a round into their car may show them that you are serious, but may also piss them off enough to where they kick into that "I don't care mode" and come after you even with a gun in your hands, taking the odds that you won't actually use it on them. You never know, they may be on LSD, PCP, or something else that helps them kick into "God" mode. Once I'm positive the situation is controlled with my firearm drawn, I'll call the cops on my cell. Thing to consider here, is that if you pull a gun on a hard-core "biker", quite often, they'll pull one on you.....or, they'll get you later. It's really a judgement call that you can only make once in the situation and depending on what you think you could get away with. It may be easier to kill them both, bury them somewhere in the back "40", and part their car out and sell it on eBay......In reality, though, I'd diffuse the whole situation by simply offering the guys a beer and we'd discuss everything in a civil manner while drinking. It does work. Have you ever seen a Harley rider drive past a bar that is open?
By the way, I ride a 1985 Harley, but I CAN drive past a bar.......only because my range time and ammo made me broke.