As usual Charley, you are once again incorrect. Laws are based on morals. And just US laws don't apply here. US, Canadian, and a whole parcel of state and province laws also apply, all to varying degrees. And then there are international agreements on top of that. Your first totally incorrect statement was:
"Nothing will change. You deal with a U.S. company, you play by U.S. rules. When you travel to the U.S., do you bring your Canadian laws with you and ignore ours?"
and then you followed with:
"However, when you subscribe to Ancestry you agree to their terms - including automatic renewal. You can't very well dispute that to which you have already agreed ... except by not subscribing in the first place."
When laws are changed to make such practices illegal, they make the agreement unenforceable. Apparently some lawmakers do see a problem with auto-renew. If it is a convenience feature as some claim, then it should be an opt-in item to the agreement. Some states have also had issues with auto-renew, see NY vs Ticketmaster for one example.
So I guess "Maybe you don't like auto-renewal, but every challenge has been found legal in U.S. courts" is also incorrect. The way a company informs the consumer and handles its policy on auto-renew does detirmine the legality of it.