"Removing the exemption would hurt the city’s housing market by causing landlords to sell off their properties to avoid losing money on their investments, said Mr. Chong of the Greater Toronto Apartment Association."

This is just untrue. As a landlord the value of my rental property investments use 2 measurements. The overall gain in equity from a rising market and from paying down the mortgage. The 2nd is rental income minus expenses. So if property values rise more quickly then rents can the investment is still profitable even if a share of the new equity value has be rolled into covering expenses like increasing condo fees or building upkeep in the case of a conventional duplex conversions.