AFAICT, that's mostly propaganda. What makes them "police" centers exactly? They do not have police men in them, don't have jails, no one has been convicted of a crime in relation to them, etc. Not sure what you mean by "abductions" but if you are referring to the Canadians who was arrested on Chinese soil, one of them admitted to espionage and is even suing the Canadian government for involving him against his will.
But people have been charged by the Canadian government over people that have been taken to China. Referring to actual Canadian court cases that are in regards to actual people taken to China is propaganda because?
Edit: Why am I blocked from replying to the below comment?
I mean, it's not like it would be out of character. Calling such accusations propaganda is a bit much.
China forcibly returned nearly 10,000 in overseas crackdown: report
https://www.france24.com/en/live-news/20220119-china-forcibl...
The Disappeared - China’s global kidnapping campaign has gone on for years. It may now be reaching inside U.S. borders.
https://foreignpolicy.com/2018/03/29/the-disappeared-china-r...
Thousands of Chinese overseas forced home involuntarily: report
https://asia.nikkei.com/Politics/Thousands-of-Chinese-overse...
40 Officers of China’s National Police Charged in Transnational Repression Schemes Targeting U.S. Residents
https://www.justice.gov/opa/pr/40-officers-china-s-national-...
China’s abductions of foreign nationals should carry costs and consequences
https://www.politico.eu/article/chinese-abductions-of-foreig...
They are called secret police centres in Canada because of the actions they pose, and the threats they make. They'll threaten to kidnap you and extrajudicially extradite you to China, they'll threaten your relatives in China, they'll force you to stop behaviours considered inappropriate by the CCP, they'll try to recruit you as a spy.
To the Chinese Communist Party, the Han ethnic group belongs to the Chinese State, and everything anyone of this ethnic background does is their business.