I disagree. The medium is at least part of the message. Art is about saying something, and what you say is fundamentally linked to how you say it.
A sonnet imposes limits on the number of lines, the number of syllables in a line, which syllables are stressed. which lines can rhyme, and a few other things.
You’re probably not going to be counting the syllables or noting down how well each pair of rhyming lines rhymes, or how many times a word has been used already when listening to a sonnet; that doesn’t mean that things like that won’t catch your ear. A sonnet which follows the rules will necessarily sound better, even to an untrained ear, than one that doesn’t, and breaking those rules might even be done deliberately to cause such a dissonance, as part of the effect you’re trying to create with your poem.
The care taken to craft something necessarily affects how well you can absorb the intended message. Appreciation of the craft and the message are intrinsically linked.
