Pescara midfielder Muntari, 32, was given a one-game ban after he protested against racist abuse he received from the crowd at Cagliari on Sunday.
The Serie A disciplinary committee said not enough fans took part in the abuse to trigger action against Cagliari.
Donsah, 20, said racism is “killing the beauty of the game”.
Former Ghana international Muntari was booked for dissent after asking the referee to stop Sunday’s match in the wake of the abuse.
He then walked off the pitch in protest – for which officials confirmed he received a second yellow card.
Donsah, who played for Cagliari for two seasons, told BBC World Service Sport Muntari did the “right thing” by walking off and said he will wear an anti-racism message under his shirt.
“I think the authorities need to lift the ban on Sulley Muntari in order to boost the fight against racism in football,” he added.
Garth Crooks, the ex-Tottenham striker and independent trustee of anti-discrimination organisation Kick It Out, has called on players in the Italian league to strike this weekend unless Muntari’s one-match suspension is withdrawn.
“I would do that 100% because racism is something that is killing the game,” added Donsah.
“Some players cutting off from some matches in order to highlight the racial abuse that is going on in football is a great move.”