That is an interesting interpretation, and while I can clearly see that as plausible for the poem, I don't believe Britten's setting of the text lends itself to the satirical. It's a cheerful/wistful rocking lullaby in the accompaniment, and very sensitive dynamics for the singer. There is an emphasis on the cooing [u] vowel, as opposed to a focus on the hard consonant sounds (usually a method for bringing out strong/negative feeling). The prevalent dotted rhythms in Britten's arrangement are also more indicative of playfulness than anything else. I was told that "wanton" in Scottish is not derogatory as in English, so I don't see much sign of bitterness, which is the main impetus for cynical or satirical works. I could, however, be convinced. ;)