Elections Canada moves to suppress free speech - wait, what?

Elections Canada has drawn a rather problematic line in the sand just two months before the Canadian federal election. It has ruled that any discussion or advertising by third parties of climate change may be deemed "partisan activity", and subject to various onerous and costly bureaucratic rules and requirements. This might seem surprising and faintly ridiculous to most people, but it appears to be a serious position taken by the independent election body.
Five out of the six main parties contesting the election agree - to greater or lesser degrees - that anthropogenic climate change is real and presents a pressing problem requiring urgent action. However, Maxime Bernier's People's Party of Canada, a new fringe hard-right political  party barely deserving of the description "main party", does not. Bernier is on record as saying things like, "The main reason for climate change is not human activity", "There is no climate change urgency in this country" and "CO2 is not 'pollution' ".
For this reason, Elections Canada argues, with some rather twisted logic, that any third party, like the charity Environmental Defense for example, that promotes climate change as real and/or an emergency could be considered partisan, i.e. anti-PPC. This would require them to register as a "third party" for the election, including all the various onerous and expensive requirements that this carries with it. It also might jeopardize a group's charitable tax status.
This is a rather ridiculous state of affairs. Climate change, and Canada's response to it, is a bona fide election issue in this election, especially given that some parties want to play it down and not take it too seriously and others want precisely the opposite. So, to hamstring the participation of outside pressure groups in this way, because of the unsupported views of one minor fringe party, is itself tantamount to partisan election interference - even suppression of free speech - if you ask me.