Ron Nachman is right. Either Ariel is not part of "Israel", and as such, is exempt from all taxes, or it is part of Israel, and must pay taxes, but then all tax-funded institutions must be available to them. You can't have it both ways.
U.S. Defense Secretary Carter: Russia escalating Syria war by targeting moderates (Reuters)
from the article: Settlement mayor sought tax cuts for city 'not ruled from Israel'