Not that it matters to me, but pure curiosity. Why would hanging the front tires off the tailgate be ok, but using a bed extender rack not? If anything I'd think the opposite would be true.
It's a very good question.
10 years ago, the bike industry was standardized and pretty much everyone had the same size front axle on their forks. Flipping the quick release off was super easy.
Now there are 3 different axle sizes on bikes. That means my buddy's bike may not even hook up to the mount on the baja. So I'd have to buy an adapter just for his fork to be able to mount to the baja. Repeat for each rider.
Also, the quick releases on bikes today aren't quite so quick. Some even require allen keys to remove the front wheel.
While it's definitely able to be worked around with some patience, it's sure nice to be able to just toss the front fork over the tailgate and away you go. No need to uninstall the wheel, purchase a specific adapter that works with your fork size (and you'd need an adapter for each mount, for each bike), store the front wheels somewhere, then reverse the process at the trailhead. I might as well just use my hitch-mounted rack which doesn't require removing the front wheel either. If I have to remove the front wheel, a truck bed is no better than a hitch rack for bike transport.
On the days when we do 3+ shuttle runs, it gets old removing the wheel every time you need to transport it.
