Firstly, the proposed law in question affects mainland Chinese people just as much as local HK people (in fact, it affects everyone who steps foot in Hong Kong).
Secondly, what do you think all those Tiananmen Square vigils held in HK every single year for the past 30 years were for?
Not disagreeing, but just want to note that there's a huge difference between the people doing the June 4 vigils (patriotic, love China, older age, want a democratic united China) and the people doing the current protest (young, unpatriotic, hate China, want independence).
I wouldn't be so sure that they're a completely disjointed set. Many who attended the vigil this year were quite young, for example, while many older people were on the streets as well today.
Secondly, what do you think all those Tiananmen Square vigils held in HK every single year for the past 30 years were for?