Very few people understand the reasoning behind CMHC.  In the past , banks demanded 25 to 30% as a down payment. Insurance companies filled the gap going to 15% down.
But some hungry builders put forth the concept of 5% down !  So just after WW2 , when the housing demand was high and vets didn't have much cash, CMHC filled the gap.
But........ is 5%, or 0% down on a house reasonable and responsible ?
Canadians meet their responsibilities. So,the CMHC premiums , the cost, is too high, if, and only if the transaction makes sense.  
No, it's not a tax.   "Old Stock" Canadians tend toward higher down-payments .