That's not my point, at all.
The fact of the matter is that in political situations, there is a calculated risk taken by both states in a diplomatic conflict. At the end of the day it is about power and what resources are required to fight this. China has the upper hand here.
On the Chinese side, they have renditioned a Chinese-born, Chinese-made, PRC-living billionaire from a Chinese SAR that's more "one country, one and a half systems" and slipping further as China can get away with it. This man's rendition is likely part of an anticorruption initiative that started a few years back, given that it was done by Chinese security services. He pissed off the wrong people in the Party and now he is having to deal with it.
As the man is a Canadian citizen, the Canadian government now has to decide how much to protest this action. Protesting actions against their citizens requires political will and/or capability of enforcement. China has already stepped over the usual line and stolen him away anyway; will the Canadian state act? This is where I am skeptical. I don't believe that the Canadian state will find that this man is worth burning more than a little diplomacy on, maybe a protest or two.
Fighting this action requires burning political capital. There is a province in which these people have become woefully unpopular; unless a lot of Canadians get really angry, there is little reason for the Canadian state to do more than informally protest through an ambassador and at best a back room dealing or two to free him (e.g. we will share financial data on Chinese-Canadian citizens if you give us our citizen back.) Either way, by making the first move China has extracted something from Canada.
To add: I also believe that the UK will not do anything regarding this rendition. They have enough international issues to deal with re: EU/Brexit and I doubt they will feel that Hong Kong is important enough to their shrinking empire to push back on China with this.