My experience is that Amazon tries to implement it's own policies to third party sellers, but, you are still indirectly dealing with a third party. If you choose "Item no longer needed" as the reason for return then you do eat the shipping costs and I think that's true for Amazon products as well. If the items is defective or some of the other reasons that's no fault to you I've always gotten a paid return label. But I do try as much as possible to not buy from third party sellers especially if the item isn't shipped by Amazon.
But, I think the TV they are talking about is sold and shipped by Amazon. "Sold and Shipped" is the choice to look for the best possible customer service where you will be dealing directly with Amazon. Not just "Prime", third party sellers can offer Prime shipping too. If you're sure that's the item you want I wouldn't hesitate at all by ordering from Amazon.
Amazon choices for returns:
Item no longer needed
Inaccurate website description
Item defective or doesn't work
Bought by mistake
Better price available
Product damaged, but shipping box OK
Item arrived to late
Missing or broken parts
Product and shipping box both damaged
Wrong item sent
Received extra item I didn't buy (no refund needed)
Didn't approve purchase
I can't find on the google for sure which you get a paid return label for or if third parties get to choose if they will pay shipping for some of these. For example "Bought by mistake" or "Better Price Available". I think Amazon provides a paid return label for everything but "Item no longer needed" for their stuff.