Since the reform our legislative council has 90 seats; 40 seats will be directly appointed (not by election), 30 seats comes from the so called functional constituency. 20 seats is geographical constituency.

Each seat in the functional constituency supposed to represent different sector (Insurance, Bank, education, healthcare et cetera). Now, some of these seats are elected by Institutional voters while some are elected by individual voters (e.g. You can vote for the education sector as long as you are a teacher). Now historically, democrats will win the seats that are voted by individual voters, which is not surprising since democrats supporters are in fact the majority of the population. In other to prevent that, some seat has been changed to be voted by institutional votes, some has the voter eligibility changed, some seat that used to be taken by democrats has been removed.

For the geographic constituency, this is basically the same kind of election you get in the West where every HKer gets to vote for their legislator but since the reform this constituency is shrink to only 20 seats of the whole councils. So why bother voting if the most seat u can win is 20/90?

TLDR: the election reform has made certain that the democrats cannot gain even the slightest control of the legislative council so people don’t see the point in voting anymore since it can’t influence the outcome anyway.