Did you even read the article? The first paragraph even says “Simply wishing to travel outside China can be cause for arrest, with Beijing detaining family members and using its political clout to force extradition of those abroad.”
For that particular area and group, yes you're right, but thinking ahead, it won't end there. Even now China is embarking on a grading system for all citizens, travel restrictions being part of the program for a bad score.
Don’t forget the new social credit system they’re launching too, that punishes “unmoral”behavior as defend by The People’s Republic.
Yep, that's the one.