The vast majority of the paramilitary forces are no more right wing than the Nazis were...it is a fiction created by the popular misconception of right and left and the desire of intellectuals to create a moral equivalency between leftists and any respectable political faction.
The problem with the paramilitaries is that the majority of them are just as prone to profitting off of the drug trade, using kidnapping to raise funds, and indiscriminate killing as the FARC (although obviously on a smaller scale due to their smaller numbers). Helping the enemies of our enemies without consideration of what it was we were siding with has been disastrous in the past, and would be so in this case as well, IMHO.