I wouldn't even be surprised if this is just a shift in marketing. The "Vegan" label, in particular, has fallen out of style as more and more men become obsessed with meat-based diets.
Keto, paleo, whatever the roid king is doing. The share of people picking that up and going "ew, vegan, it'll probably turn me into a soy boy" is probably bigger than the share of people who only buy vegan products, OR the savings of cutting those 6% of natural ingredients are worth losing the latter share of buyers. Bottom line is the company's bottom line.