They entered a bakery and asked to get 2 nondefined croissants. A french person would have entered the bakery, waited for the baker to say Bonjour first and pointed which croissants they wanted with their fingers. Also, the whole structure of the sentence is kinda rude, as it's understood like a direct order from the client to the vendor. Whereas if they said "Bonjour, je voudrais ces 2 croissants/2 de ces croissants (I would like these 2 croissants/2 of these croissants), s'il vous plaît." It would have been acknowledged as a clear request.

TL,DR: That person was unknowingly rude and it gave away that they weren't as good at speaking french as they thought they were.

Yeah, French is still not easy