That bit I boxed red is about Article 23 which half a million of us — including all of our family, John then aged six— demonstrated against in November 2003. The big worry there is “theft of state secrets” — we know China has a veeeery broad interpretation of what “state secrets” are. And the bit about “foreign political organisations or bodies” could cover just about anyone including this blog, I guess.
Hong Kong Basic Law Article 23 (Chinese: 香港基本法第二十三條) is an article in the Basic Law of Hong Kong. It states that Hong Kong "shall enact laws on its own to prohibit any act of treason, secession, sedition, subversion against the Central People's Government, or theft of state secrets, to prohibit foreign political organizations or bodies from conducting political activities in the Region, and to prohibit political organizations or bodies of the Region from establishing ties with foreign political organizations or bodies."