I don't understand why the world in general is worried about Hong Kong being taken over by the Chinese. In 1842, Hong Kong was a chinese territory. It was taken

I don't understand why the world in general is worried about Hong Kong being taken over by the Chinese. In 1842, Hong Kong was a chinese territory. It was taken over by the British during the first and second opium wars and then leased out to the British for 99 years. The keyword here being leased out. If now China is wresting back control of its territory, how is that disputed. The people of Hong Kong always knew that their autonomy was only till the time when the lease ends. Interestingly, When the union flag was raised over Possession Point on 26 January 1841, the population of Hong Kong island was about 7,450, mostly Tanka fishermen and Hakka charcoal burners living in a number of coastal villages. Today Hong Kong's population is 7.5 Million so 1000 times its original population. So every body who came later knew about the lease and the length of the autonomy.