Louqe is based out of Sweden, the USA has zero authority over Sweden based companies which have no business presence in the USA.
Tariffs are applied to imports and are applied to those who import the products attracting the tariffs. In this case it will be the individuals who live in the USA who have purchased the case, if the tariffs are applicable to the case and are collected by US Customs.
I think we should ask Louqe in Q&A coming soon. They may have a US based subsidiary for tax purposes, and for shipping in bulk, and posting through Amazon (i think they are using them for internal US shipping - according to their shipping email). I think if they are importing under this subsidiary, then the subsidiary is liable for the tariff? If so, it would be up to Louqe on whether to pass on the cost to the customer. I'm no tax expert by any means, but i think thats how it works. I would be surprise if they pass on any additional costs for the 1st batch, but who knows for the 2nd.
It doesn't take a lot to set up a subsidiary in another country, if you intend to be shipping alot of items into said country. Amazon probably require you to have one.