Why am I charged VAT on shipping?

Because in Europe VAT is levied on all “incidental expenses”, including transport and insurance charged from the end-customer.

Article 78 of the VAT regulation:
The taxable amount shall include the following factors:
taxes, duties, levies and charges, excluding the VAT itself;
(b) incidental expenses, such as commission, packing, transport and insurance costs, charged by the supplier to the customer.