Not all Canadian travellers will be affected. Most Canadian citizens visiting for tourism, shopping or short-term business don't need a visa at all — so this new U.S. travel rule won't change anything for them.
However, Canadian citizens do need a non-immigrant visa for certain travel reasons, such as:
Joining a U.S. fiancé(e) (K-1 and K-2 visas)
Completing a family immigration process (K-3 and K-4)
Working as treaty traders or investors (E-1 and E-2)
Serving as diplomatic or international officials (A, G, NATO)
Assisting in law enforcement operations (S-5, S-6, S-7)