One obvious point to make in passing: even if there is some kind of profound connection between someone’s political leanings and the form they choose when they write a poem*, that connection is not stable over time.
It meant something different to be writing sonnets in 1520 than to be writing them in 1820 or 1920. And something different again in 2008.
Or at least, if anyone wanted to suggest otherwise, I’d need to hear some pretty convincing arguments.
* Or paint a picture, or build a house…