re-Consider:
Dentist - private sector, provides service, earns income, pays taxes. how does the dentist get payed? buy your :
   insurance, company benefit or out of pocket.You know exactly how much that visit costs you.
Doctor - public sector, provides service, earns income, pays taxes.
how does the doctor get payed? well you walk out the door and a bill for services is rendered to the provinces health ministry.You have no idea how much that visit costs the province.
Do you not see the difference?
The CRA job is to  only collect taxes,the source is  irrelevant , and turn them over to the government.