So one of the "Militia" members arrested in Michigan is a registered Democrat; while another apparently hated George Bush. At a minimum, it doesn't sound like they sat around discussing the evils of Harry Reid and Cap-'n'-Trade.
Most self-described Christians lean right, but, if I recall from surveys I've seen, about a third of those on the left in the US also identify as Christian. Often, despite believing some or a lot of what the left proclaims, such people identify themselves non-partisan, citing their (very low priority, obviously) disagreement with the Democratic party over abortion, and perhaps a few other social issues. Jim Wallis is a perfect example. Some of them are well-adjusted, nice people (Wallis seems to be), but it's also true that the few angry and disaffected Christians I've met have uniformly been on the left. (Consider the sermons of Obama's minister.) So I'm not shocked at the discovery mentioned above.
The question of "orthodoxy" is also significant. Christianity, more or less (depending on denomination) is a religion whose beliefs are derived from the bible. The belief Jesus will return is certainly biblical, but the belief that one should call 911 in order to inflict harm on an innocent responder (if indeed, that is true) certainly is not. Murder is quite unorthodox, doctrinally. As would be making a naked, F-bomb laced video wearing a George Bush mask. Their reading of the bible (if they consulted it at all) would undoubtedly be a rather "liberal" take — one which conveniently places them at the center of history.
Next: There's a rare strain of Christian belief (which the left likes to depict as typical) called "dominion theology". While the bible (as far as I can see) depicts the return of Jesus as being something only God determines, in contrast, many of these people believe they can "usher in" the kingdom of God through some sort of political action. In my experience most of these are on the left (and believe the "kingdom of God" is spread via government mandates towards socialism) but the Hutaree also fits this bill, obviously.
Finally, there's the belief that only the right wing can be interested in weapons or violence. This is, frankly, ahistorical nonsense. The impression probably comes from the fact that it is the right in the USA who are primarily concerned with legal self-defense — but it's also true that there are quite a few on the left who agree with them. (I know quite a number of gun-toting progressives.) Historically the left has generally been quite comfortable with use of force, but generally either on the part of the "legitimate" state (favored political groups or causes) or the political vanguard (revolutionaries). Castro didn't take power by nonviolent means, after all, and Oliver Stone doesn't condemn the violence he employs to keep it.
So my point here isn't that said militia group is left-wing (thought they may be), nor, even if they were, that an entire group should be judged by the actions of a fringe (as my political opposites would argue) — but more that this probably isn't going to work out to be the neat partisan point many seem to hope for. Mainstream conservative Christians generally want to live in peace and go about their business. If there's an apocalypse coming, it's going to be thrust upon them unwillingly, not created by themselves for their own political aggrandizement.
I urge... that requests, prayers, intercession and thanksgiving be made for everyone — for kings and all those in authority, that we may live peaceful and quiet lives in all godliness and holiness. [1 Timothy 2:1-3]
Do not repay anyone evil for evil. Be careful to do what is right in the eyes of everybody. If it is possible, as far as it depends on you, live at peace with everyone. [Romans 12:17-18]
Make it your ambition to lead a quiet life, to mind your own business and to work with your hands, so that your daily life may win the respect of outsiders and so that you will not be dependent on anybody. [1 Thessalonians 4:11-12]
In contrast, one of the core beliefs shared by most revolutionaries (the US Founding Fathers being a miraculous exception) is that the revolutionary is part of a tiny minority who are fit to rule or control the lives of others. All such revolutionaries are "anti-government" in the broadest sense — they don't like any government which isn't theirs (meaning the current one). In contrast, normal conservatives and libertarians tend to be distrustful of powerful government per se, regardless of who is in charge.
Of course, it's absurd that I'm writing on the defensive here. Where was the media when Karl Rove's house was being besieged daily? Why was the media seemingly disinterested in the man from whose home Obama launched his political career — Bill Ayers? Where was their crack reporting on "a rising tide of violence" when it came to attacks (and even attempted murder) of conservatives at the Minnesota GOP convention? Where was their touching concern for "extremism" when it came to depicting some of the truly scary behavior at "anti-war" events throughout the last administration?
Didn't fit a desired narrative, it would seem.