Do you know what he was doing when he was passing through (yes he was just passing through) destabilizing the Sandinistas, though the ads suggest that he was very active in all that, it's equally likely that he was just training contras, which is something that one can do all the way into your... wait there dosent seem to be a limit on that, unless you can't speak.
And if you want to just get on the Alan Moore hating tip there are more plot holes to work with, like the fact that he drunkly stumbles In his Uniform to Molochs house (nobody notices in a town whos streets are always full), or the fact that apparently Laurie has been living with Dr.M for years but acts like she's known him for as long as we have (the whole "what do you mean.." thing on mars, seriously you've lived with this guy forever but you don't know he can turn coke to pepsi??!!)