To be honest I can kind of understand that perspective (even as someone who choose to study English at university, and enjoys Shakespeare, on the whole).
A quarter of kids don't meet "expected standards" for reading at KS2, just before Y7, and while I'm not that familiar with what exactly that means in practice, I'd guess that struggling with reading would make reading actual Shakespeare texts very tricky, even with the normalised spelling and grammar, and copious footnotes, that you get in student editions.
A 400 year old play with archaic language and almost entirely unfamiliar cultural and other references, paced and structured according to C17 expectations and circumstances, doesn't seem like the most versatile text for a mixed-ability group, or the most useful kind of text for practising various skills with. You couldn't reasonably expect the whole cohort to be able to read and understand the full text in the original, so you're looking at summaries, performances, and maybe a little bit of work with the original text here and there.
If "doing" Macbeth means being exposed to some Elizabethan/Jacobean theatre, getting a feel for the broad span of literature and drama in English, looking at how characters and themes are developed, thinking about how literature fits into its historical context, discussing dramaturgy and staging and adaptations, and other types of learning that don't necessarily require reading and understanding the whole play from the words on the page, while other important aspects of English are learnt via more accessible or transparent texts, then that's great.
If it means expecting every eleven-year-old to be able to slog through and understand full-length playtexts written in a highly stylised, allusive, poetic version of Early Modern English, and spending weeks and weeks focusing solely on something that's just going to bore kids to death and put them right off studying literature in general and Shakespeare in particular, then yeah, that sounds dispiriting and not very productive to me.
I assume that secondary school English teachers know perfectly well that "doing Macbeth" with Y7 in the same way you'd "do Macbeth" with A Level literature students (who are able readers and have chosen the subject) would be counterproductive. So while I can kind of sympathise with the idea that it seems crazy, I'd hope that "doing Macbeth" in y7 is something that takes into account the fact that they're young kids with a wide range of reading abilities.