It is unfair to renters because renters do not have an equivalent 100%, completely unlimited tax-free investment vehicle. We have Tax-Free Savings Accounts, limited to ~$5k contribution per year, and we have RRSP's with max contributions scaled to income, but homeowners have access to all those things too, and they are limited. Homeowners can take advantage of TFSA, RRSP, and then shove all of their remaining savings into maxing out their home purchase and enjoy all of their gains completely tax free. Renters have to start paying capital gains at an inclusion rate of 50% once they max out TFSA/RRSP.
This system is completely unfair and places a higher tax burden on renters who are, on average, less wealthy than homeowners. It encourages us to spend more than we should be on housing just to get around taxes, and discourages investing in actual productive things like innovation/companies.