the song that forces men to leap overboard in squadrons even though they see the beached skulls (4-6)
Women and men are certainly polarized (put on different sides) in "Siren Song," with the former being the sexy seductresses and the latter being the duped sailors. So our speaker may be offering some of the stereotypical characteristics we often see in literature regarding the sexual roles men and women play.
I don't enjoy it here squatting on this island looking picturesque and mythical (13-15)
We really get the sense here of women looking isolated and "mythical" in terms of their sexual roles in literature. Meanwhile, our speaker isn't enjoying her "picturesque" world that's been painted for her. Here we sense the limits of the kind of two-dimensional drawings of women and femininity in myths.
at last. Alas it is a boring song but it works every time. (25-27)
Well of course it's a boring song if it gets the same results every time. The song here may also be a symbol for the sorts of roles women play in literature that are boring and predictable. But, on the other hand, those dead sailors are equally boring since they too play the same role of being easily deceived and seduced. But hey—"it works every time."