Sullum links to three of his own articles. In each article he assumes that because Obama discusses the issue, then he must agree with Sullum's preferred resolution. Sullum provides little argument for why his preferred resolution is the correct one.
At the heart of Sullum's misunderstanding is that he is looking at these issues from an outcome determinative perspective. Sullum wants a certain outcome and appears happy to break a few eggs to get there. Obama, in contrast, appears to be very technocratic and process driven. He wants to preserve the process and function of American government, even if that means that he doesn't always get what he wants. In fact, on many of these issues it can be a little unclear what Obama actually wants as a policy outcome because his public focus is on process. For example, he could have pulled a Clinton on the health-care bill and written the damn thing in the white-house and then shipped it to Congress for approval. Aside from the strategic reasons not to do that (see, e.g. Clinton, presidency of), my reading of his choice to send it to Congress so Baucus could dither away at the thing for months is that Obama wanted Congress to write and pass the law... you know, like they're supposed to.
At the heart of Sullum's three articles is this single complaint: Why isn't Obama acting like a dictator, by-passing congress, and bringing about my preferred policy outcomes? [I LOVE the fact that this argument is coming from a libertarian, btw] Well, aside from the obvious strategic reasons [just imagine, for one brief second, how quickly articles of impeachment, illegitimate or not, would be drafted in Obama unilaterally re-scheduled pot], there's the overarching concern that making large scale policy decisions which undermine legitimate laws passed by congress is a pretty scary thing for a president to do. I know I threw a fit whenever Bush started hinting at that sort of thing. Party affiliation should not over come concerns about abuse of power.
Addressing Sullum's remaining arguments from the linked articles in turn:
Clemency for Crack Disparity - Yes, Obama could, in theory, grant clemency to everyone imprisoned under the crack sentencing guidelines. He could also, in theory, grant a pardon to every single prisoner in America, effective immediately. Were he to do so it would be the largest abuse of presidential power in my lifetime. Sullum never even considers that such an act of clemency would be incredibly destructive to American democracy. Hell, it would probably bring me to the barricade walls. Do I think the crack/cocaine disparity is horrible? Yes. Do I want a president to steamroll congress, ignore legitimate laws, enact my preferred outcome, and to hell with the structure and function of government? No.
The other two articles are a bit different. The abuse of power/dictator concerns aside, Sullum really doesn't seem to get that just because Obama says he understands the concerns about the war on terror or the NSA, that doesn't mean that he agrees with Sullum. In short, on both of these topics Obama has not "said one thing while doing the exact opposite." Rather he has said, "I hear your point, and I disagree."
Terrorism - Sullum's linked article discusses how Obama outlined the various perspectives on the war on terror and how the war is pursued. He acknowledges Sullum's perspective. But because he has not adopted Sullum's preferred policy, then Sullum throws a fit. Apparently, it never occurred to Sullum that Obama might just disagree with Sullum, even though he understands his arguments.
Privacy/NSA - In the speech discussed in Sullum's article, Obama worries about the threat to privacy from the intelligence community. He repeatedly insists that in his review of the program he believes that it has been operating in good faith and within the boundaries of the law [he may be wrong about this, but it is what he says]. Obama says he believes we're striking the right balance, but that others do not and so ....[yada yada yada, establish a commission, etc.]. Sullum, again, is upset that although the president has recognized the privacy concerns inherent in signals intelligence, he has not abolished the NSA. It never appears to occur to him that Obama simply disagrees with him as to the constitutionality of the programs, whether they are authorized by law, and whether they are being abused. Instead, Sullum assumes that to recognize the privacy arguments is to adopt Sullum's preferred outcome.