It’s more accurate to say that the British prevented either themselves (through inaction) or China (by treaty/law) from having any practical control. If you’d bother to read the wiki article OP linked you’d know. China should have had jurisdication, but Britain techincally had (imperialist) jurisdication. The result was a no-man’s land until Britain finally gave up.
EDIT: missed a word
I’ve been testing out Bluesky. Too early to give it a final rating, but it’s been cool (if relatively empty) so far.