While it is true that even under Hu, HK government was pressured to take orders from the mainland government, it is evident that the current regime is less tolerant to any democratic opinions. HK government is forced to implement the "National Anthem Law", and is planning (I believe still a rumor, but most likely the truth) to pass the controversial Hong Kong Basic Law Article 23.

At least during Hu's time there was still some minimum open channel (advocated by Chief Tsang) between the democrats and the mainland government. Now, there is none. There is no compromise on anything coming from mainland.

There is absolutely no flex under Xi's regime. I used to be quite pro-mainland myself, but in recent years I have switched my position after seeing how the mainland government is overreaching the One Country Two System.

"Hong Kong is being repressed" does not mean that Xi is meaningfully less liberal, overall.

How has Xi changed life for citizens of mainland China - the 99.5% of the population that does not live in Hong Kong? How has it become more authoritarian for them?

Every time I've asked this question, the answer has always involved Hong Kong - as if it is representative of China as a whole.

Nobody considers Puerto Rico to be representative of the rest of the United States, or Gibraltar to be representative of the rest of the United Kingdom. Hong Kong is, in a similar vein, a poor litmus test.