I think the tense nature of this topic isn't from the forum being "whiny" or "getting mad over nothing"; it's because art is complicated, everyone's journey is different, and everyone has different goals. One shoe does not fit all, and that's why it rubs some people the wrong way.
If an artist came up to me and asked me if studying fundamentals was necessary to being good, I would say ABSOLUTELY, in a heart beat. Its importance should not be taken lightly. And in comics, artists often need to be jack-of-all trades to boot: we need to be able to draw almost anything and reference will take you a long way to being able to do so easily. Not to mention, writing skills within a comic format are just as important, such as narrative, pacing, and all the basics needed to just make it readable.
If your goal is to make this a career, and if you care about self-improvement, then yes--doing studies consistently over time is good advice.
But let's say this person buckles easily under pressure, is only trying it out, wants to do it purely for fun, is comfortable at their current level, or just DIDN'T ASK for any advice on how to improve. Under any of those circumstances, I would not try to push studies or techniques on them. They are making it for different reasons and taking that extra time will either paralyze them or waste time they could be using to create content.
The key here lies in if the person wants it or not and if you are imposing your views on people unfairly. No matter how experienced you get, you can not dictate what other people should do, nor should you judge them for approaching art in a way different from yourself!
In my younger years I was similarly very bothered by people--professional or otherwise--that allowed themselves to stagnate. "Such wasted potential!", I thought, "If you're not always growing you're not a real artist."
That was horseshit. Fact of the matter is, they had their reasons, and I had no right to impose my value set on them. Especially as I've worked in comics more, I've come to understand that producing content quickly hinges on developing a comfort zone, which is at direct odds with rapid change. And if you don't produce quickly, you won't be able to pay the bills. That doesn't mean that these artists will NEVER IMPROVE, but it's slower.
You as a creator will have to decide where you want to walk that line, and it's no one's decision but yourself! Same goes for everyone else here.
For the record, I don't think you were trying to be controversial or malicious in any way. But I hope this sheds some light on why some people get upset. Like everything, the situation is best viewed in nuance.