I just read through the current application form here, and stepped through the simple questions here and here, and see no such requirement.
There is a spot where you can enter your anticipated travel dates (including an 'unknown') option, and to my recollection it has been there a long time. Intended for those people needed expedited services if possible.
Please link to where you've seen the 'mandatory proof of travel'.
I read too fast.
That new rule about proof of travel only applies if you need your passport in 25 business days or less, and only if you apply in person.
Found this info in the last 2 links you posted (you need to select Applying from Canada, and then select in 3 to 25 business days) :
"If you’re applying in person and need your passport in 3 to 25 business days
You must provide proof that you need the passport. New"
"New" is highlighted in green in the text, so I figure it's a new regulation.
Thanks for the correction.
Still a good idea to get a second citizenship and second passport though, just in case Canada goes full commie in the next few years.