immanence versus transcendence
Free will has always been tied up with transcendence in accordance with the usual inside/outside scheme. Free will, human, white, male, nihonjin, straight, etc. invents a category in which it, a priori, i.e., via presupposition and for convenience, is superior. Transcendence is code for "how I/we/inside is special." False dichotomy. Everything is the same, first and foremost. Differentiation comes after. The difference between rocks and humans, causally speaking, is complexity. For humans, there are considerably more forks in the road than there are for rocks. Difference of degree, not kind. Every now is a fork in the road, or a billion, but the vast majority will stay on the main road, i.e., repeat.
teleology versus spontaneity
I played baseball when I was 6 or 7 and was absolutely terrible. People kept telling me to keep my eye on the ball. It didn't make sense, though. How could I hit the ball just by watching it? I wanted to follow through on the advice, but every time the ball approached, I'd try to watch bat and ball at the same time and bring them together. Lots of terribly painful, emotionally scarring strikeouts followed. I ended up being a solid softball player as an adult, but only after learning to watch just the ball while letting my hands and the bat magically send it into the outfield. It still doesn't make sense to me how it works, it just does. The expectation makes it happen. I don't even know how I brush my teeth. There's so much happening there. Cells in arms and hands and air being displaced and so on. Then there's the internet.
The question of randomness, as far as I can tell, is set against this teleological backdrop. Is everything set in stone or not? In other words, has everything already happened? The argument that everything has already happened (again, I think this is mostly hidden) would be a big leap from predictability, which is quite limited to observable repetition yesterday, today, and tomorrow. Predictability versus unpredictability is about human brains evolving in a now and mastering spacetime in their proximity, or failing to. Randomness versus unrandomness is speculation about a divine clockmaker that is modeled on the weirdness of our own godlike powers. Randomness is a failure of predictive power, nothing more. Moving on.
it is what it is -- everyone is a compatibilist
All of this is in reference to The Way Things Actually Are. Like all of us, Dennett and Harris use words produced by never-the-same-for-even-a-moment (moments themselves being freeze-framed abstractions) brains to create truth in a now, with TWTAA at the same time being assumed, whether they or we acknowledge it or not, to exist on its own. If some "revolutionary" new truth is created in the course of this debate -- something that most humans brains will be moved to believe and be affected by in the way brains are affected by beliefs -- its impact will likely be trivially small. People did not stop sleeping, eating, screwing, and killing when they heard about biological evolution. Hell, the majority of atheists are statists who think, like Hitchens and Dawkins, that yeah, maybe "we" should invade and destroy those Muslim societies and teach them the true and good ways that civilized people do things.
But apart from, and far more important than, the question of how much this debate matters is the question of how it matters. The only way incompatibilism, the belief that if humans are clockmaker determined all is fucked, affects you, in short, is if you buy it. It's determinism as apologetics. My body is making me go to the liquor store now. OK, I believe that, and now I'll just go. Determinism, no check that, the belief in determinism, is potentially causal, as an excuse. That's how it matters.
Simply by acting, on the other hand, as humans do, you're a compatibilist. Say you learn that, in accordance with TWTAA, everything is fucked. Well, you continue to act 99.99% the same as before. You're still breathing, yes? That's acting. Are you dead? That's acting too. Body still be worlding when you dead. The only way the debate matters is as yet another cause in this ongoing, ever-fluxing humanness we only understand by referring to something that, as far as anyone knows, only lives in our heads, i.e., TWTAA.