I've been anticipating the advent of this issue ever since the stamp was announced late last year. There is no doubt that the topic is politically controversial:
The Komagata Maru Incident of 1914.

The blurb in Details No.3 April recounts how Canada turned away 356 Sikh immigrants who could not pay the required $200. Twenty of them returning to India were shot there.
I am entirely uncomfortable with this issue - which is, I presume, the reaction
Canada Post intended to provoke. I would be interested to hear what others of you think of this.