In each of these components Amazon Basics has an advantage over third parties whom are often mom and pop and are undercapitailized.
The points of contention are
1) If amazon competes fairly in Ad bidding so Basics products shows up first on the paid search results, is this anti-competitive?
I don't think so. They just have more capital. Any other well capitalized firm can do the same.
2) Is it fair for amazon to display their products more prominently?
I don't think so. How is this any different than Walmart refusing to carry a product? Or putting their private labels more prominently?