It's not a tax rate of 75% that is being discussed (according to the article), it is an inclusion rate of 75%. Right now capital gains are included at 50% - so a $1,000 capital gain counts as $500 income, at a 50% combined federal and provincial marginal tax rate the total tax paid is $250. A 75% inclusion rate would mean that the total tax paid is $375. This would hurt me a lot personally, but I don't think it is especially unfair. One would still be able to offset capital gains with capital losses, which is a big difference from ordinary income.