The shipping rates are certainly weird, and I do think they should be reviewed, although I think the internal rates are too high, but I admittedly don't know the cost structure.
They would probably be cheaper if they weren't subsidizing postal rates for other countries.
I find it amusing when you have a problem on AliExpress and the seller suggests you mail it back to them. Unless the product has a very high value it almost always costs more than the product's value to send it back to China.
Luckily AliExpress customer service seems to realize this and will often grant refunds without requiring you to return the product.
eBay really sucks on this regard; it's very difficult to get a refund for a defective item without paying handsomely to ship it back.
Most of the sellers know this and simply ship you a new item or refund you though — at least for comparatively cheap items.
Pay with your PayPal account and we can refund your return shipping costs if you need to send anything back – up to $45 per return and 8 returns each year.