Why is there a charge for uploading text messages on mobile phones?

One-way charging for sending short messages, that is, sending charges, is determined by the tariff policy. There is no special reason.

Technically, whether you send or receive, it takes up network resources.

However, because the short message fee is relatively cheap, it is generally 1 corner 1. It's too much trouble to charge 5 cents for sending and receiving.

When you reply to a text message, you send a text message. According to the tariff policy, if you want to collect money, it can't be said to be a trap.