It is considered CSS [1], which makes sense to me as this relates to styling. What has never made sense in my mind is to have completely unstyled pages rendered with microscopic fonts on smartphones. Doing so for old sites that, at the beginning of the mobile revolution, assumed on their CSS sheets 1024px wide screens is reasonable (though still debatable). Not so for CSS-free pages, whether they were authored in 1991 or in 2023.
I'm sorry if I got carried away, I wasn't replying to you in this last part :) For the record, I would also make this exception, though it would be neat to be able to select those without even the meta viewport tag.