as another commenter pointed out, it may well have been over 3.5% of the Hong Kong population, but it was by no means over 3.5% of the Chinese population
3.5% of what? There are international, national, provincial, and local authorities, each with different constituencies, all of which overlap to some degree.
The preferred method of coup by powerful external forces who finance them are color revolutions - usually via arming violent extremist groups with controlled opposition leaders. That’s about all I need to know.
An American analogy of your argument would be something like “but >3.5% of LA wanted policy XYZ, why didn’t it work”
-- used 10B world population for simplicity.