"I don't think it's normal that I have to pay for all these shipping costs" - Please read the following to understand why: 

We strive to keep our prices as competitive as possible while maintaining the quality of our products. Offering free returns/shipping would significantly impact our operating costs, which would ultimately reflect in higher products prices. Our goal is to provide the best value to our customers upfront, rather than incorporating potential return costs into every purchase. 

In summary: free shipping/returns will automatically turn into a higher product cost, because in the end we also have to pay the shipping company (it's more than normal for delivery drivers to be paid for the job they do, right?). We want to avoid incorporating potential return costs into every product, because this would have the effect of making our products too expensive and no longer affordable for everyone, which is exactly what we want to avoid.

Also: If I have to pay all my customers' shipping and return costs to FedEx myself - after paying the VAT and taxes - I will barely make a profit. This is obviously not the intention given that this is my full-time job and I also have to pay bills.

Thanks for understanding.