The supply chain for most "local" vehicle manufacture in North America winds back and forth between Canada, the US, and Mexico. None of those countries can assemble a finished car without parts coming from both of the others. Trump hates this and has been doing his utmost to torpedo the system.
The risk with Chinese cars has less to do with the cars themselves and more with getting too deeply enmeshed in, and dependant upon, trade with China. ~50000 cars a year isn't going to do that in Canada, though, since at the moment we're wary of putting too many eggs into any basket.
Cracking down on this stuff on Facebook can reduce the number of instances of this kind of thing by reducing the scammers' reach (so still worth doing), but not make it vanish. Snake oil has a very long history, after all. It plays to a common element of human nature: the desire for a quick and easy fix where none exists. The only complete solution is to produce smarter humans, which, well, good luck.