@Angle China doesn't really have a way of doing that. What you're referring to is shadowbanning, and it is practiced on western sites, like say Reddit, especially to fight spam. In those cases it's easy to tell when it's happening, just check from a different computer if your comment is still there. China can only block whole websites, through the ISPs. From there they can bully sites into removing content (or else!), but they can't always do it themselves.