What does it matter whether TikTok is a security threat (although it clearly is). In what other trade context would it be acceptable for one country to block a

What does it matter whether TikTok is a security threat (although it clearly is). In what other trade context would it be acceptable for one country to block all access to its own market (e.g Facebook, Twitter etc) whilst still enjoying full access to everybody elses? How is it remotely unreasonable to treat China in the same way it treats everybody else?