This may occur especially if you are trading for the first time. In certain countries, sellers are required by law to know who their customers are. Most sellers explain in the terms of the trade if they require ID verification or not.
Sellers will be able to see if you are verified with Coindirect, however we do not pass on your verification documents to the seller.
If you do not wish to give the seller your ID, you can always cancel the trade and search for a seller with less strict requirements.