That really only adds to my suspicions. I'm not blaming you, or anything; but it's a pretty straightforward fact that when a society gets divided between two political/ideological factions, these become lightning rods and the opinions of their adherents become increasingly polarized even if the actual positions and behavior of the faction leadership is virtually identical. It becomes far more about identity than anything else. "We" are right, sane, rational, good. "They" are the opposite. As a more objective outsider, I won't claim that they're equal. They clearly aren't; but I've certainly noticed that those on the American "Left" are themselves just as susceptible to black and white thinking as those on the right. By and large, they tend to be more reasonable; but not when they're implying nonsense like how if Bush had been in charge he'd have started WW3. That sort of a belief is just an expression of oppositional thinking born from factionalism.
As to why that just adds to the suspicion; it's quite natural for those who have strongly held a particular political/ideological/philosophical position to swing to an oppositional extreme when they get disillusioned. Having been on 'both' sides of the partisan divide doesn't make you more likely to be unbiased; but rather less likely.
Having said that, what I find most disturbing about Bush et al is how much they seemed to believe their own narrative. Invading Iraq was supposed to end with the Iraqi people welcoming us as liberators, like WWII soldiers liberating France. Dancing in the streets and a wholehearted embrace of democracy was sure to follow. It would not at all surprise me if these clowns honestly believed they could invade Russia and keep the war from going nuclear.
While I don't disagree with the believing their own narrative bit; the democrats are really no different in that regard. And there's a huge difference between believing that Iraq would welcome them as liberators, and deciding to invade Russia. You're subconsciously employing the same fear-mongering tactics the Republicans often engage in: "If these guys (who I just happen to be on the other side of in the political divide) were in power... IT WOULD SPELL OUR NUCLEAR DOOM". There's more than enough material to criticize the republicans with without having to devolve the discussion to the level of an average paranoid-laden slice of Fox News.