this is an excellent topic that needs attention. it's nice to see that Etsy is also doing their part to combat this. admittedly, i have reported a few shops for reselling beauty products as handmade, that are clearly off-label and designed for resale.
i think from a buyer's perspective, to protect yourself and know that you are buying from someone that truly made the product, you need to ask the seller some questions. if they can honestly talk about their product, either by description of their process (without divulging trade secrets), origin of materials, function, etc. you can ensure that you are buying from someone that actually made the item. If the response is sketchy or lacks in substance, there is probably a reason to move on and purchase from another shop.