Royalty rates aren’t a tax.
You see, the non-renewable resources that oil and gas companies extract from the ground (bitumen, oil, natural gas, coal, etc) are public resources. They belong to the public: to you and to me. We collectively “own” them (as far as anyone can own anything that was here before we were).
Corporations shouldn’t be able to come into a territory and extract publicly-owned resources for free. If the public is going to allow them to extract that publicly-owned resource for profit, then the public should be reimbursed for that.
Royalty rates are input costs for a company. Just like a textile company pays for bales of cotton or a vegan burger company pays for bushels of peas.
Alberta is the supplier of the oil, and the bitumen, and the natural gas, and the coal. We, the people, are the supplier; the provincial government simply manages it for us, so we don’t have to. And as the supplier, we’re entitled to charge our customers for the products we sell them.
Royalty rates aren’t a tax to corporations. It’s an expense. Like worker wages, or equipment, or utilities, or printer paper.
Just because the government happens to be the supplier doesn’t mean it’s a tax. And just because the supplier of one of your costliest expenses happens to be a government doesn’t entitle you to low tax rates.