That's cause the customs still exist for goods that come from extra european countries, those goods need to be inspected an so on, and VAT is applied. I don't remember the exact taxes but there is like a 10% fee for something, then another 11-13% fee for something else, plus something like $15 for "the service", 'cause the couriers that import those goods anticipate that 20-23% to the customs offices and then apply this $15 additional fee when they deliver at home.
It's not a fair procedure, for example some countries only pay these fees for goods that worth over $300 or $400, here in Italy there's the customs fee even for goods that worth $25 and over. And it's very subjective, you never get to know exactly which % they apply and they can keep you packet for weeks, a friend collector of mine purchased an item with free shipping so on the packet shipping was placed as $0 - the customs office decided that it was wrong and considered as if shipping was $100, so added $100 to the packet value and places the 20-24% fee on the total price. And he never got to talk with someone of these offices, they only have help numbers that are no more active, they don't answer to e-mails and you just get lost in a sea of burocracy. They dodge any question or problem you raise.
And, as stated in the previous page by another user, there are a good amount of ways to avoid this useless taxes, for example Switzerland and Ireland give much lower taxes for import and so on.
That's why I'd prefer to give more money to Sideshow instead to random people that only watch your packet, open it, throw things away and treat your goods -for which you pay lots of money- like horse ****.