It's not that they no longer support the idea of a plant-based diet, it's more likely that plant-based diets are so overwhelmingly supported by the evidence that they no longer have to keep saying it out loud.
Especially since their recent articles seem to echo what their position paper on vegetarian diets already said years ago. To them, it's like common knowledge.
That said, they are one of dozens of dietetic and health authorities around the world who have made it clear that a plant-based diet can not only be appropriate for all life stages, but it can be used to reverse certain diseases (i.e heart disease and T2 diabetes) when other diets simply can't compare.