Except that the siren has been the cause of recent disasters. We saw her luring sailors to their doom in the first chapter and it's why the village is especially jumpy as opposed to simply prejudicial. More interesting is his decision to fill his ears with wax to resist her song since that's a trope from the Odyssey which he can't have read and wax as earplugs isn't the first thing I'd think of.Blaming the siren with those mishaps when that humongous beast is the one causes those shipwrecks.