That doesn't however mean omni itself is head-hopping, just that bad writing where the writer attempts omni tends to include it. You can also head hope in something that is obviously meant as limited third, and it would still be what it is. In that case, badly written limited third.
My disagreement is subjective and temperamental. In the visual arts we have say primitivists, expressionists, impressionists, and cubists, and one can call their technique "bad", when compared to the realist schools, but it becomes badass, when judged by its own standards. In a sense, technically speaking, much of Picasso or Monet can be called "bad art", and one can point fingers at relevant bits of ancient art textbooks as proof, but... Come on. Likewise one can't say that punk rock techniques are "bad" while prog rock techniques are "good", and vice versa; jazz drumming is not "better" than blues drumming, and so on.
I've ran across many a head-hopping bits in great books (head-hopping as in vortex of limited thirds with no hovering narrator), and would have to make a conscious effort to force myself to see those bits as "bad". Seen naturally, by me, they are a) head-hopping, and b) awesome.
Just like, in a way, Lovecraft's "bad writing". Oh no, he has no dialogues, oh the horror, his prose is baroque. I love reading his prose. I read him not so much for the story, as for the way it is written. I'm far from the only one. He's great at what he does and should be judged by the criteria one uses to judge this vintage vibe subgenre, not by the criteria used to evaluate a Stephen King novella, less still a Hemingway or Elmore Leonard one.
To wrap up--I can see how people may need, as a psychological crutch, for one reason or other, a conviction that certain techniques are "bad", in spite of them actually working for millions of readers/listeners/viewers, but
my psychological crutch is to foam at the ears whilst doing my damn best to point out that fashion in writing or any other art/craft is one thing, while treating this fashion as objective rules of good and bad as per proof discovered in underground volcano prose-collider secret labs, just because twitter diva editors and writers use the topic as visibility and prof cred props, is quite another, vastly sillier thing.
Warning beginner authors that head-hopping, unless done in the context of amazingly brilliant texts, can close doors because of current fashion and prejudice, is, IMO, being realist and objective, and doing said beginner authors a favor, not least of all because it trains them to see another aspect of technique. Saying it's bad and shouldn't be done because it's bad and shouldn't be done, is a shared mild psychosis which will last another decade or two at most. Or shared mild neurosis. Something like that. Harmless in itself, but stifling for certain people, who, without these socially imposed restrictions, may have actually created vastly superior works.
EDIT: Having said that, the things we discussed in this thread have helped me enormously in understanding certain nuances, for which a big thanks to everyone. I hope my babbling will also spark something off with someone; possibly something quite unrelated, but we take what we can, in the sparking off business.