Well enjoy the Mayweather centered episode... there aren't many. Which is a pity because I kind of thought the freighter culture was interesting too, at least until it got repetitive... yes Travis... we know you live in space... and apparently all there is to do is have sex.
Now... to the meat of the episode... well I can sum this up easily. Archer is stupid. "What gives you the right to take prisoners?" Okay... would you rather them have killed the fellow? Or just let the pirates loot their ship? Both seem worse to me. The whole premise of the episode is hey... Starfleet isn't protecting them. So yeah, I think they have every right to defend themselves.
Archer then expresses concern that by taking a prisoner they'll incite the Nausicans to be aggressive... yeah if you're not careful they'll start attacking your cargo ships or something. Now don't get me wrong, I don't think that torturing the Nausican for information was the right thing to do, but these are YOUR people Archer. Take the prisoner, promise the Fortunate you'll take care of things, call up Forrest and have him file a diplomatic protest to their government. That's how you handle things.
The Fortunate did take things too far by retaliating... but Archer wasn't offering ANY sort of alternative. Indeed he actively sides AGAINST the people he's supposed to be helping forcing the confrontation at the end. Between the Fortunate and the Nausicans... and him and his own people. I mean, if Archer's the best Starfleet has and he can't even manage basic diplomacy... the Vulcans are right, they need to stay at Earth.