Agreed that Amazon should make it clearer when it is the actual seller, but, in your example, you knowingly bought from a third party. Why would this affect your future purchases from Amazon when Amazon is the seller?
What I dislike is when something has prime listed on it and when you look closer it's not even sold or shipped by amazon. Just some company that "meets the requirements". I use amazon's prime because their warehouse in 30 minutes away and I get stuff same day or overnight.