Unless I missed it in the article what exactly is the simulated attack? Are they flying real planes over US targets? Wouldn’t that in and of itself be considered an act of aggression?
In case the new U.S. administration failed to get the intended message behind all that provocative military activity, four days after President Biden took office, a large force of Chinese bombers and fighters flew past Taiwan and launched simulated missile attacks on the USS Roosevelt carrier strike group as it was sailing in international waters in the South China Sea."
Countries do acts of aggression all the time. Last June 20 Indian troops were killed in Himalayas clash with Chinese army. The political question is when it is enough to declare war.