Well, based on what's here so far, here's my hot take: most people, artists included, don't understand art advice. ^^; They don't understand how/when to give it, or what it means when they receive it.
And I think the people who give it are the most at fault; because it's usually their over-eagerness that causes those who receive it to start getting the wrong ideas about it.
Like, for instance, the dreaded 'same-face syndrome' usually does not apply to simplified art styles. To accuse Adventure Time of same-face is ludicrous and doesn't make any sense...but people WILL do it, because learning about a 'rule' for art makes them feel knowledgeable and like they have to spread it around somehow, even if they don't know what they're talking about.
To give another example: the recent Twitter discourse about 'flipping' your artwork to make sure it looks good. It quickly devolved into a war between people who think flipping is necessary and people who don't...but that isn't actually the point. ^^
As one very wise person put it, flipping is a TOOL. It is just a technique, like doing a sketch before you draw lineart. And the point of this technique is to 'reset' your brain and your eye for proportion so that you can judge a drawing clearly.
But...you don't have to flip to be able to do that. Some people just have that knowledge ingrained already; some people have other methods (like putting the drawing away and coming back to it later). The fact that someone doesn't flip doesn't mean they're doing something wrong.
And most important of all: you don't judge other people's FINISHED artwork by flipping (i.e. the OP in this discourse was definitely in the wrong). If you flip a piece of artwork and find it looks screwy; it's probably because you literally reversed it and your brain isn't used to seeing it that way, not because the artist failed somehow. If there's a legitimate flaw in the drawing, you shouldn't need to re-arrange it to detect it.
I could go on and on:
This means that understanding how something works IRL will make you better at stylizing it, NOT that you should somehow study realism 'completely' before being able to stylize anything.
On the other hand, I think focused style study is a much better road to developing and improving a style than 'staying in line' and learning a bunch of preliminaries first. Take it from someone who's been working in stylized art for several years and has never once really studied anatomy. ^^;
People who are experienced with stylization understand how it works, and you can pick that up by paying attention to what they're already doing; you don't have to link it back to some lesson in realism. Those links DO exist, but they aren't always necessary to learn how to emulate a style.
Like, if all you need to know is the fundamentals to automatically understand how to stylize, then you'd think artists who focus on realism would be effortlessly good at switching to cartoons, or even just anime. But many of them are really not. BOY are they not. ^^ It's still a separate skillset.
Basically, if someone is struggling with stylized art, I wouldn't necessarily say it's because they 'skipped the line'; I would say it's because, regardless of how much they skipped or didn't skip, they're looking at stylized art and not yet understanding what those techniques mean and how they work, and if there's anything they need to learn first, it's that.
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TL;DR, a lot of art advice is used incorrectly, and a lot of it is flat out bad. Receivers, learn the difference between advice that's accurate but hurts to hear and advice that is actually inaccurate/inappropriate, and you will avoid a lot of drama.
And Givers...calm the heck down. Just because you learn a 'special rule' doesn't mean you need to immediately look for any context where it might possibly apply and badger people into accepting it. Very few, if any, rules are ALWAYS appropriate for EVERY context...especially when it comes to art.
