Based on my knowledge, a term of matcha should refer to green tea that is commonly consumed in East Asis countries, such as Japan or China. At least, one of famous known online encyclopedia, Wikipedia support my understanding.
However, the picture showed that in some cafe, matcha doesn’t always green. Matcha can be brown also.
Perhaps, the barista thought matcha is only tea as she didn’t know that matcha is a term specifically made for green tea, not brown one.
(Bogor, 2022)