Fair comment...
I'd phrase it (as others have already done):
"Anyone planning to go to Canada should have found this out"
Look... I live in a different hemisphere.. and I found out that sort of detail before going to Canada for the first time... it is no different to establishing whether you need a visa, can get it on arrival or not etc etc
Who said it was a safety or security issue? That link simply says the CBSA determines eligibility to be admitted in accordance "with Canadian Law"...