It's racism / anti-China rhetoric. Usually when they talk about foreign investors they mean Chinese investors specifically. There have been a number of studies that have completely discredited the idea but it perseveres. Canada's housing market never really went through the same contraction that the US housing market did. Prices have just continued to increase for 20+ years. I would hazard a guess that most people buying houses today are paying more than 10-20x their annual income for it.

Because housing has reliably increased in price for a few decades now there is a relatively large number of people who own more than one house and rent them out. In fact many people will turn their basement into an apartment (which is honestly the worst fucking thing, I haven't personally rented a basement apartment but many of my friends have and it sucks). It's just an awful situation. Obviously the conditions that lead to Mao were much worse with landlords having extreme control over tenants lives, but it is still a tremendous burden on the Canadian populace. So we won't get a Mao any time soon but man the situation sucks.

I have zero empathy for even "mom and pop" landlords for this reason. There's a lot of nonsense in the news talking about corporate landlords vs mom and pop landlords and they are both terrible. Mom and pop landlords might actually be worse because they scrutinize and dehumanize their tenants more because they don't farm it out to property managers who are paying their staff minimum wage to barely give a shit.