Yes he is a cellist, but he has played violin and has mastered both cello and violin.
yo yo ma also plays the piano, viola, and violin. his occupation is listed as cellist, composer, and pedagogue, in that order. violinist is not one of them. he has no body of work (recordings or famous performances) on the violin, so he is not known as a violinist.
we go by what a person is known for, so to speak.
we know winston churchill as a great british wartime prime minister and writer, not as a painter, though he did paint well.
the name james joyce conjures a great novelist, not a poet and playwright, though the guy wrote good poetry and plays.
famous romanian sculptor constantin brancusi was a good cook. no one called him a chef.
perry como was a barber, but we know him as a singer. sean connery was a truck driver. must we call him a truck driver?
i play (ugh!) the guitar and the violin. i’m a housewife to my friends, not a guitarist or a violinist.
one day you may be known as a great doctor. your current background in biology and some units of islamic studies would not make you a biologist and an islamist.
Linkback:
https://tubagbohol.mikeligalig.com/index.php?topic=30891.0