I know why China is upset about it. They know that a large percentage of the population of Hong Kong doesn't want to be part of China.
And they have done everything in their power to make sure that the Hong Kong independence movement doesn't gain a foothold. From punishing protestors to eroding local autonomy, to encouraging mainland immigration, to manipulating global speech.
This isn't about some disadvantaged country being sensitive because they were taking advantage of by colonial powers a century ago.
This is about a modern colonial power asserting dominance over an oppressed people.
>I mean, I get that you don't like them
Yeah I don't "like" a government that puts millions of people in reeducation camps because of their religion. A government who most likely executes political prisoners to harvest their organs.
I don't like a government that insists that the populations of Taiwan, Tibet, and Hong Kong have no right to self-determination.
If you don't dislike such a government, I'd suggest that you are the one being willfully ignorant.