I don't think you need to get too worked up about this. According to this article, from the CBC, the increase to 10% ethanol is just to regular gasoline. So not ALL gasoline, which would protect the supply for aircraft, whether that was 100LL or the "hi-test" ethanol free MOGAS available at select retail locations. AVGAS would fall under the federal government's watch and that would be a huge battle.
Ontario looks to double amount of ethanol in gasoline
Interesting to note that the ethanol producers were the biggest corporate donor to the Ontario Liberal Party but I guess that is typical politics. Guess they are making sure a big cheque will be delivered in time for the next election campaign.