Is it against Amazon policy to sell Non Branded items on branded listings?

I have two large competitors doing this.

My understanding is the brand on the listing should be permanently affixed on the physical product or packaging?

The competitors are stripping out every possible cost of production including selling generic items under branded listings, thinning out magnetic backings to the products while claiming they are a certain thickness etc etc all the while propping up listings with fake reviews. Doing this they benefit from lower production costs, shipping, storage and fba fees allowing them to sell very cheaply and squeeze the market.

Amazon's brand policy states the following "Branding on products and packaging must also be permanently affixed."

"Sellers are prohibited from using a misrepresentation of an existing brand on their ASINs. For example, you cannot use Amaz0nB4$1c$ in your ASIN’s brand attribute if you are trying to list an AmazonBasics product."

But it also states the following so it's confusing.

"If your products or packaging are not branded, but you have a registered trademark for your brand, you can enroll in Brand Registry, which will allow you to list ASINs with your brand’s name as the brand value."

Although the brand have a registered trademark it was not registered by these two companies.