Hello,
Due to WC plugin docs
Related Products is a section on some templates that pulls products from your store that share the same tags or categories as the current product.
https://docs.woocommerce.com/document/related-products-up-sells-and-cross-sells/#section-3 All products from your screenshot have the same tag, that’s why you see them as related products.
If you don’t want to show these products and want to choose what products to show then I would suggest you to disable related products in Theme Options and enable Upsells (change position of up-sell products from “sidebar” to “After content”).
Regards
