Are China's Tantrums Signs of Strength or Weakness?

China is supposed to be savvy. So why is it throwing a fit about a tweet, an app, and a gamer in a mask in the absence of any real threat?
Read more: https://www.theatlantic.com/international/archive/2019/10/why-does-china-care-about-daryl-moreys-hong-kong-tweet/600001/?source=Snapzu