The article continues beyond that line.

They outline, with numbers, the practical effects of rent control in the sample size of metro Toronto.

I’m not an economist but I didn’t think consensus was a valid benchmark against empirical data.

Those (The few of those I could actually read, thanks paywalls!) all focused on the effects on owners bringing rental units out of the market and don't really show that there was an overall decrease in the number of housing units available. The economist article for example doesn't have any real info on the effect of rent control just the fairly standard arguments about it affecting the willingness of land owners to build.