There's a difference between stocking your own products alongside the alternatives and marketing your own products to the exclusion of the alternatives.
If you're doing only one or the other, there's no problem. If you're doing both, there's a serious asymmetry and you are taking money from the alternatives' suppliers under false pretenses. The suppliers expect to be on equal footing with its competitors. At this stage, Amazon's products should be considered one supplier out of many and shouldn't be offered special treatment because it belongs to the retailer.
When you walk into your local grocer, they aren't putting all the house brand stuff in the front and hiding the name brand stuff in a stockroom where you need to specifically ask for it.
If you're doing only one or the other, there's no problem. If you're doing both, there's a serious asymmetry and you are taking money from the alternatives' suppliers under false pretenses. The suppliers expect to be on equal footing with its competitors. At this stage, Amazon's products should be considered one supplier out of many and shouldn't be offered special treatment because it belongs to the retailer.
When you walk into your local grocer, they aren't putting all the house brand stuff in the front and hiding the name brand stuff in a stockroom where you need to specifically ask for it.