It's because it's game over for abusive RE investors (many newcomers) buying houses and saying its a primary residence when it isn't to avoid taxes, and not rent out because that would be more obvious that it's not primary residence. Bill doesn't want more people to get into fraudulent dealings, and doesn't want to tip off people that are avoiding taxes, as to make sure government can recuperate those tax revenues cost-effectively.

But the real problem is our excessive immigration! which is excessive demand for housing distorting the market, way too many newcomers over the last couple of decades, but especially since the 2008 crisis. Not to mention too many skilled TFWs that aren't being required by employers to transfer their skills to Canadians and then being sent back. Too many provincial finance ministers getting transfer payments, for bringing newcomers, instead of for better provincial programs for growing Canadian family population. Email Bill and PM about these problems!