Well, my first post here :-)

Seems the question is: R'osity "Marketplace" or R'osity "Store"?

If "marketplace", the business is between the customer and the merchant, the marketplace owner only let the infrastructure. He lays down the general rules. He will not control every single pea for quality, it's the job between the mearchant and the customer.

If "Store": see blondie9999's good example: the supermarket:  No need to repost it.
BUT: If I know that there are goods arround the supermarket will not sell, it's my good right to ask why they don't want to sell it. And if I get a rude/stupid/unsatisfying  answer, it's a possibility to vote with my feet.

R'osity calls itself a "marketplace", R'osity names the merchants as merchants and not as suppliers.
We are customers of the merchants. We don't buy from, but via R'osity and use it's infrastructure.

I only read arguments against Bobs opinion saying in different words:
R'osity was a store, is a store and will be a store forever, regardless of the naming, my way or the Highway!

IMHO R'osity should reassess it's position.
Just my 2 €-Cents
  karlchen