You have to be pretty selective in this article to look at one word, "perceived", and conclude that the issue here is that people aren't trusting their pediatricians. If the paper meant to say that that vegetarian weaning was a snake oil treatment, it would have said that a lot more directly.
Instead, it literally says: "Vegetarian weaning with appropriate guidance from family pediatricians or nutritional experts is possible and it should not be opposed."
If the paper meant to say that pediatricians were fully up-to-date on how to give advice, and the problem was that nobody was listening to them, then it would have said that a lot more directly. Instead, it literally says: "Efforts should be made to enhance nutritional understanding among pediatricians as an unsupervised vegetarian or vegan diet can cause severe nutritional deficiencies with possible detrimental long-term effects."
I don't think a full reading of the entire paper supports the conclusion that pediatricians are perfectly informed and that vegetarian weaning is a snake oil con. It supports the conclusion that research is underdeveloped and that many pediatricians are not qualified to guide parents through that process. It does discourage vegan weaning because it's difficult to do correctly, because it can go very wrong if not done correctly, because we're still getting research about the best ways to handle those diets, and because, again, pediatricians and health experts have not studied these diets enough to be confident giving advice about them. This is not necessarily the same thing as saying that vegan weaning is impossible to do well -- it's acknowledging that we live in a world where it hasn't been scientifically studied enough to know the potential downsides, and where guiding resources are extremely scarce.
I think you're projecting a conclusion onto this that the authors explicitly reject. A paper that was trying to warn about the troubling trend of parents rejecting their pediatricians' advice would not look like this. It would be talking about things like combating disinformation, it wouldn't be spending half the paper talking about the best B12/iron/etc vegetarian food sources.
But it never goes to topics like misinformation. Instead, it lays out nutritional advice, warns against unsupervised weaning and the risk of naively eliminating meat, and then ends by reinforcing again the need for proper professional guidance: "alternative weaning as a self-decision should be generally discouraged. Pediatricians should guide families strongly willing to follow a vegetarian/vegan regimen, providing all nutritional requirements."
That doesn't line up with the narrative you have about this paper. Nowhere does it say, "pediatricians should figure out how to convince families strongly willing to follow a vegetarian/vegan regimen that they're being scammed/deluded."
> There are plenty of articles in the mainstream press by doctors who lament the fact that their patients will trust charlatans who sell them energy therapies and other such snake oil treatments, instead of the doctors themselves.
I'm sure there are. It's just, this paper isn't one of them and shouldn't be lumped into that category. If you're writing about energy therapies, you don't spend half the paper describing how to do energy therapy well and how we need more resources to guide parents through energy therapy, because it's not a real thing that can be done well.