These are private schools, privately owned. The Israeli government doesn't subsidize private schools in Israel that don't teach according to the Ministry of Education syllabus. The fact that government funds are diverted to Haredi "educational institutions" that don't comly with this rule are a bone of contention in the country right now. I seriously doubt that Arab private schools comply with the israeli Ministry of Education subject syllabus.
Yemeni Shiite rebels to form own Cabinet in 10 days (AP)
from the article: Rightists furious over Palestinian plans for new East Jerusalem schools