If the seduction-as-entrapment unfolding in the shadows at the start of “Stockade” rings a familiar bell about the abuses of power, it should. If the cacophony of vying voices and damning accusations piercing the town hall meeting at the start of Act II of Henrik Ibsen’s “An Enemy of the People” strikes a chord, it should as well. In this election season, a theater company can take it easy on its audiences.