Even offensively challenged teams have guys who can hurt you. Conforto and Alonso are 2 of the best young power hitters in the game (Alonso might be the best power hitter period).
Offensively challenged teams can't string together 5-6 hits in a row, but they can hit homers. What the Mets did was hit multi-run homers. All of the Sox homers this year have been solo. Any pitcher will tell you they really don't care about giving up solo homers; they don't hurt you any worse than 3 singles, and in fact are probably better since once the guy crosses the plate, you start clean with no one on base.