Why do I pay extra costs for Paypal?

Paypal offers extra services to protect customers when buying online. It is like an insurance. Paypal is also very expensive. We pay 4-6% extra costs on top of the costs of a creditcard or bank transfer. 

We do not think it is fair if we have other customers pay for the insurance that some of our customers want via Paypal. 

We therefore ask the customer to pay their insurance fee theirselves.