This is the correct interpretation of this issue.

All of a sudden, millions of people who are quite happy to be fence-sitters about all sorts of injustices across the world (Many of them in their own countries) have decided to draw the line on China and Hong Kong.

According to them, anyone who does not explicitly support pro-HK politics is an enemy, and must be punished accordingly. (Even if what they want is a no politics policy.)

This is, of course, the same sort of 'with us or against us' behaviour, that those same fence-sitters criticized when it came to other injustices...