The first is that I think part of what’s happening here is a corollary to Hitler's famous thesis about the role of "Big Lies" in politics (something Small Precautions has commented on in other contexts, as well). What Hitler acutely observed was this:
The magnitude of a lie always contains a certain factor of credibility, since the great masses of the people in the very bottom of their hearts tend to be corrupted rather than consciously and purposely evil, and that, therefore, in view of the primitive simplicity of their minds they more easily fall a victim to a big lie than to a little one, since they themselves lie in little things, but would be ashamed of lies that were too big.
The bailouts are the macroeconomic equivalent of a "Big Lie" – they represent a grandiose gesture, one ratified by Bush's admonishment in October that if the bailout wasn’t authorized, then "this sucker could go down." People were outraged by the bailouts, but at the same time, the very scale of the government's action signified the awesomeness of the executive. In other words, the bailouts represent a classic case of the political sublime – terrifying, and yet somehow worthy of respect by sheer grandeur in scale.
By contrast, using taxpayer money to pay the executives bonuses at a failed company seems like mere everyday corruption, petty and small. Instead of a sign of the government's awesome power, it is a sign of the Obama administration's weakness and impotence, a point underscored by AIG's message to Geithner that heand the taxpayers could basically drop dead.
Unlike Bush, Obama clearly hasn't mastered the political art of the Great Lie. Readers can judge for themselves whether they consider this a good or bad trait in his governing style.
My second thought about the anger about the bonuses is that what's really in play here is not just anger at taxpayer money funding executive bonuses, but a deeper resentment about executive excess in general. Whereas the bailout money could be justified as a necessary payout to prevent the sucker from going down, and thus as having some positive social benefits despite its hideous price, it's almost impossible pettyfogging to try to justify AIG executive bonuses as being somehow about protecting the system. What's more, the claim that those bonuses are a necessary part of the system (which is the basic argument for why the bonuses need to be paid), then it seems to underline the essential corruption of that system.
This explains the tentativeness of the GOP's and the wingnutosphere's attacks on the AIG bonuses. On the one hand, they recognize that it’s a useful stick with which to beat up on the impotence of the Obama administration. On the other, its underlying political emotion comes from a place that is dangerously at odds with the GOP's political culture, namely anger at arrogant executives. What's risky here for the GOP is that anger about AIG executives’ bonuses (or Citi's $10M executive suite remodel, or car company CEO's riding on executive jets, and so on) can easily spill into a generalized revulsion to outsized executive compensation and perks in general—which is of course what the GOP stands for, culturally.
And therein lies the real danger for the GOP's Richistan constituency: that one of the longer-term outcomes of the economic crisis is a cultural shift away from tolerance for the excesses of the corporate elite. Long-term economic downturns, particularly ones that seem directly linked to the excesses of the rich, usually do produce "Soak the Rich" demands.
Update: Kevin Drum gets it: it's the culture of executive overcompensation "that deserves to be dismatled brick by brick."