Not allowed to pay for car in cash, must finance, is that legal.?

I am interested in buying a car in the state of New York. I am from out of state but I saw a car I really want on a dealer's website. So I contacted them for further information. I have great credit, a good income, and money in the bank. The car I want to buy is $15,000 and I have enough money to pay completely in cash. But the dealership will not allow me to pay in cash. They are saying that they will only let me go through financing for the car with interest rates 2.8%-15%!! I don't need financing, I can pay for the car completely up front. I don't want to go through financing and all that. Is this legal for a dealership not to allow me to pay for a car completley up front? I haven't signed anything or bought the car yet but I questioning how legitimate this policy is. Are there laws against this. If so I need official sources cited please (remember the car dealership is in New York, NYC particularly).

I wrote a check for my current car, the dealership wanted me to finance. Why pay interest if you don't have to? Tell them you will buy elsewhere. If you MUST have THAT car, finance it for the shortest term and pay it off next week.

You don't need official sources! Go with your gut. You know this doesn't *seem* right. Walk away from this deal... no, RUN away from this deal. Trust your instincts. This smells bad.