Harassment interception of security center in Xiaomi mobile phone cannot be blacklisted. What's going on here?

Your own software does not support it. It can be set by third-party software. My current Tencent mobile phone housekeeper supports setting black and white lists.

Tencent Mobile Manager has intelligent cloud interception function. Can intelligently intercept stranger numbers, intelligently intercept all harassing calls and things. Will not intercept normal phone calls and text messages. You can also set new interception keywords under the black-and-white list design at the same time. The interception rate of spam messages is as high as 98%.