Should car insurance be included in the price of a car? You have the freedom to purchase insurance from whoever.
But even if it is true, I think the price of the insurance (or at least some reference value for comparison, assuming there are multiple competing offers) should be included in the sticker price.
For the same reason, purchase-money lenders (in a buy-vs-lease situation) typically require the debtor to hold a comprehensive insurance policy until the vehicle is paid off. It protects their interest.