I think they should probably accept "shirt" as a translation for بِلوزة since it is more commonly used nowadays, but "blouse" is probably a more literal translation.
I did a google image search for بِلوزة رجل and many images came up. They are all what I would probably call shirts.
In India, the word blouse is used ALL the time, for a specific type of tight women's shirt worn with a sari. But I understand that this word is no longer used so much in the native English speaking countries, but for others who are learning Arabic through English, but are also speakers of other languages, the word 'blouse' may be perfectly normal.
In Romanian, it's bluză. My guess is that like "garage" and "t-shirt", it's a word that an English speaker would understand. Would completing the Arabic language Duo Lingo course make me fluent? No, but it would help if I wanted to take courses further down the road, or go for a visit to an Arab speaking country. No perfect language course would be offered for free!