The Dutch equivalent of They drink beer or wine? is Ze drinken bier of wijn? I think it's fair to say this roughly has the same feeling and usage.
The standard way to turn They drink beer or wine. in a question in English needs the auxilary verb to do, so Do they drink beer or wine? In Dutch the standard way is to switch the subject and the verb, so Ze drinken bier of wijn turns into Drinken ze bier of wijn?
So translating a Drinken ze bier? to Do they drink beer? is closest. I think in Duo They drink beer? is not accepted because there is the standard, more common way (with do) to translate this, which is closer to the Dutch original sentence.
It's just like in German. When asking a question in Dutch, such as "Drinken zij bier of wijn?" In German, "Trinken sie Bier oder Wein?" Both translate to "Do they drink beer or wine?" The verb 'to do' is implied with the main verb 'to drink'.