Email also isn't very popular in China. I'd surmise it has something to do with the popularity of instant messaging in the new generation internet users.
Using email feels cumbersome compared to WeChat. Of course, you pay the price of having a single app do everything but most people don't even register that as a potential threat.
Yes. Also the fact that half of the west's trigger-happy sysadmins banned all Chinese IP addresses from virtually any cross-border SMTP activity because 'spam'.
Not sure if you're sarcastic, but that's literally all I get from there. Spam and brute force attempts.
The IP addresses fail2ban unbans are banned again 2 to 5 minutes later.