Sorry, but this article is terribly flawed
First, Jon mentions withholding taxes. Those are almost irrelevant. Jon goes on to correctly focus on the 46% marginal tax, that is what will be the ultimate taxes paid when trued up at tax return time. Focus on the 46%, forget the withholding tax (except yes the cash needs to be there).

If you take $5000 out you need to account for 46% tax so it should be only 2700 left to grow and be taxed at 50%.

The article at one point correctly mentions that the tax man contributed 46% of the RRSP. So, the correct thinking is a 46% tax on withdrawal is just the tax man taking back his 46% share of "your" RRSP. He was a partner all along. Your 56% share grew tax free!!

The article states the RRSP is merely a tax deferral. Absolutely false. Your 54% share grows completely tax free if marginal tax rate unchanged at 46%.

Notions of freeing money from RRSP to save taxes are mostly utter nonsense. The proper math and thinking will lead you to let it grow.