By that framing you are saying that Toronto, Montreal, and Vancouver should also all seek secession.
Likewise, you could say that NYC and LA should singularly secede from America by that same logic.
It doesn't track. There is no legal precedent. Alberta as an entity did not exist beyond Canada.
Canada is a confederation/confederacy. Ie your central government is weak and your provinces are strong. They can leave just like Quebec. Quebec has to be bribed to stay.
> There is no legal precedent.
Legal precedent doesn't really matter here. If Alberta wants to leave and they're willing to fight a war over it, then that's up to them. USA already went through this once.