Why are a few words in some short messages just a bar?

In order to prevent keyword blocking, ISP or some mobile phone firewalls generally block words with high frequency of spam, short X-mail (the principle is the same as spam and X-mail). In order to send information to users more reliably, these people who send spam, X-mail and X-mail will use special character segmentation (you say-) or homophonic instead.

I also blocked some key words in my answer.