On a familiar compatibilistic picture of what things might be like, all our free actions are determined by our proattitudes and beliefs. The proattitudes provide the drive and ends for the action and the beliefs tell us about what does and does not conduce to those ends. On the most traditional version of the story, the proattitudes are noncognitive. I think Warren Quinn's arguments against such a view of proattitudes are sound: noncognitive proattitudes just do not render action rational. I would say they are too much like mere dispositions to act, and dispositions to act, every bit as much as the actions that flow from the dispositions are in need of being made rational. Thus, the proattitudes must have a cognitive component: something like a seeing of an end as good or a judgment of an end as good.
Now consider this dilemma. We either do or do not always act in accordance with the rationally superior attitude. I.e., we either do or do not ever act in accordance with what the attitude presents to us as the rationally called for or the better course of action. If we always do, then we are never blameworthy. For while the judgments embodied in our proattitudes may be wrong, we are not blameworthy for these wrong judgments if we came to them always acting by our better lights.
Blameworthiness requires that at some point we have been responsible for acting against our better lights.
Now, proattitudes are either entirely cognitive or have a cognitive aspect and a conative drive/motativation aspect. If they are entirely cognitive, then when we act against our better lights, then something other then proattitude must be determining our action in cases where we go against the better judgment embodied in these entirely cognitive proattitudes. But on the compatibilist picture, it is being sourced in our proattitudes that makes an action be truly ours. And in the relevant respect, the respect that determines us on the wrong (by our lights) rather than right course of action, the action is not sourced in our proattitudes.[note 1] That makes it very hard to see how we can be responsible.
Next, suppose that the proattitudes have both a cognitive and a conative component. On this picture, the cognitive component is what makes actions rational and the conative is what causally explains the action. On this view, when we act against our better lights, it is because proattitudes with a rationally weaker cognitive component can nonetheless have a causally stronger conative component. But how can we be responsible if that's the ultimate explanation of our wrongdoing? For it is the cognitive component that makes for rational action, for action that is distinctively personal, the sort of thing that is subject to moral evaluation. Imagine taking a brute animal and adding a cognitive component to its noncognitive proattitudes, but keeping the root of the deterministic causal explanation of action on the noncognitive side. That would not make the brute responsible. It would just create a monster.
When one is determined to act in accordance with the rationally weaker but conatively stronger proattitude, one is in the grip of a disorder, a kind of disease of the will (we call it "akrasia" or "weakness of the will"), which causes one to choose the rationally weaker rather than the rationally stronger course of action. But one is not blameworthy for such diseased action unless one is blameworthy for the disease. However, since the story applies all the way back, there is no room for blame left.
This line of thought does not refute the compatibility between responsibility and determinism. For it says nothing against the compatibility between praiseworthiness and determinism. But I think it gives one reason to think that determinism rules out blameworthiness.