I don’t know. His english mistakes are very plausible just typical French grammar mistakes and his viewpoint is not incorrect and in fact most likely true for the overwhelming majority of visitors. Perhaps the tin foil is sitting a bit tightly...

The use of the phrase "white card" (carte blanche) is telling.

However, we don't need to resort to tinfoil to point out that their anecdote misses the point. "Don't be political" is poor advice when Canadian citizenship is perceived through a political lens.

I don’t think PRC propaganda would so blatantly invite people to come visit but keep their mouths shut while visiting. They probably wouldn’t promote that they police speech so heavily.