Much like Taiwan, PRC cannot simply smash the place up and say "obey us or else." That would hurt themselves in a very direct economic sense, as HK and TW both are important markets to the PRC. What we're seeing happening before our eyes is Tiananmen Square anno 2019: false flag violence from protestors, planted evidence, planted counter-protestors. The PRC is trying to sell the narrative that the protestors are wrong, it is the only way the protests will be quelled without literally killing them all.