Countries have an obligation, via their publically-funded postal agencies to deliver any mail/courier to their citizens. This was fine pre-internet as roughly s

Countries have an obligation, via their publically-funded postal agencies to deliver any mail/courier to their citizens. This was fine pre-internet as roughly same amount of mail was sent as received on average -- so countries invested roughly the same amount of manpower. But in the case of china/Ali-express, it receives maybe 1 for every 100 mails it sends out, which means receiving countries use proportionally much larger manpower to distribute the mail, and this is via tax-payer funds. So interestingly, that you yourself end up paying for china's free shipping, via your home-country taxes.