Israel's public school system can teach/not teach in the language it chooses. If the arabs in Jaffe don't like the decision, they can leave, or form their own private school system. I'm sure they don't tolerate Hebrew language or Jewish people in Gaza/West Bank.
Sunni Arab nations are 'Israel's allies,' says Israeli Foreign Ministry director general (JTA)
from the article: Ban on Arabic in Jaffa classroom sparks protests