This has been so for many decades.  Back in the 1970's countries to which Canada was not removing were referred to as "IS 26 countries" after the Immigration Manual reference that gave policy directions to Immigration officers.

Certain countries have been so designated over the years - a temporary suspension of removals (TSR) halts removals to a country but  it  is not permanent and is subject to changing conditions.  Iran, Iraq and China have been listed in the past and it was policy during the Cold War to not remove citizens of Soviet Bloc countries

Currently per s. 230 of the Immigration and Refugee Protection Regulations, the Minister of Public Safety has the authority to impose, maintain or lift a TSR.  Often work and study permits are offered as special processing for permanent residence on humanitarian and compassionate grounds.

Here is the TSR for Haiti and Zimbabwe (now expired):
http://www.cic.gc.ca/english/resources/manuals/bulletins/2015/ob600.asp