I mean, you are technically correct. If you earn more than approximately 800k in Quebec, you would pay about 50% of your income in taxes. But how many people earn remotely that much? Is this really a concern for us mere mortals?

Average tax of 50% is pretty hard to hit you are right but I was more pointing at marginal tax rate which is what most people refer to when they say Canadian income tax are high. Just check the CRA tax brackets and add in the Revenu Quebec tax bracket for instance.