1- voting got implemented over there only a few years before the handover. It's a relatively new and fluid concept to them.
2- industries/businesses get to vote. These are increasingly owned by China
3- China maintains veto power for any political candidates
If only it were as simple as "just vote"
We have a lot of poverty here so it's very easy to buy votes by just hosting a dinner at a average restaurant, telling the people all the wonderful plans you have for HK then giving them a trinket to help them remember to vote for you.
This is a false narrative originally perpetuated by VJMedia.hk, pro-democracy activists in League of Social Democrat that managed to gain traction on English internet via QZ. The primary sources (FCO40/327 and the Thatcher memo) used to substantiate these claims has nothing to do with democratic reforms but UK seeking HK sovereignty as a self-governing dominion like Singapore (not just democratic reforms) as an alternative to handover because it would stabilize investor fears - the concerns were purely economic. Obviously China would reject this proposal which basically tried to circumvent handover by making HK dejure independent in 1997. The reason why UK/Patten introduced some democratic reforms near handover was a last minute effort to maintain some political and economic influence over the colony. There was never any effort in the 60s to grant HK democracy within the context of Extension of Hong Kong Territory lease - they asked for sovereignty which was never an option - and what little that was given was a last minute geopolitical power play.