That's utter rubbish. Hong Kong had very little covid until they lifted all precautions. UV and HEPA were still relatively rare, and mask requirements were (a) surgical masks and (b) came and went throughout the pandemic.
And it worked. In 2020 cases were in the hundreds per month. Sweden, with only a slightly larger population and far more dispersed, was having thousands of cases a day. Hong Kong, in the first 2 years of the pandemic, had 213 deaths. Sweden had nearly 18,000
It is wrong to say that Hong Kong had very little covid until they lifted all precautions.
It is right to say that Hong Kong lifted all precautions because they had an awful lot of covid.
Masking started pretty much universally in January 2020 without prompting from authorities, and then became mandatory for most of the 3 years. It didn't come and go.
For the first two years the draconian border restrictions seemed to work, we watched the cases per day at stay at 0 for months, then 0, 2, 4, 1, 4, 10, 20, 5, 4, up and down in very low figures. It seemed to be working, even though there was literally no end in sight, HK seemed to have won, as long as you didn't mind wearing a mask forever, checking in with an app to each shop or place of business you visited, or having 2 weeks quarantine in a hotel every time you returned from travel. If someone in your building tested positive, off you went to forced incarceration for 10 days.
And the cases and deaths stayed low.
And then, omicron happened.
And the cases rose. And fell! Then rose again. And rose.
And rose.
What was 10 per day on average became 20, became 50, 120, 200, 500, 2000, and then in a few weeks it was over 75,000 cases per day, that's 1% of the population newly infected per day. And those were only the confirmed cases from PCR tests, the real number was of course far higher.
This all happened whilst all those same restrictions were STILL IN PLACE.
At this point, even the Health Authority had to admit that pretty much everyone had already been exposed, but they kept on with the same restrictions. Then it emerged 200,000 people had left HK permanently in the first quarter of 2022 due to those very restrictions.
So gradually in late 2022 restrictions started to be slowly loosened, as it was clear Zero Covid was not working, and there were rising calls from the population to live with it. Again, social stability was threatened.
It was only after China turned on a dime and stopped its own zero covid approach that HK finally lost all its restrictions, and stopped mandatory mask wearing in early 2023.
https://www.worldometers.info/coronavirus/country/china-hong-kong-sar/
There was no sudden wave of infections that happened after all the restrictions were lifted.
All the peaks on that graph? Restrictions still in place.
"Utter rubbish?" Sorry, no, you simply don't know what you are talking about.
EDIT: "And it worked". Yes, until it didn't.