That's not the injustice. The problem is that Alberta's political interests are very poorly (if at all) represented federally. This has come to a head a few times in the past with things like cancelled pipeline projects or the NEP[1]. So the issue is that Alberta has 11.52% of the population, contributes 15.25% of the GDP, yet must constantly fight against policies that put it at a disadvantage or run counter to its political leanings.

[1] https://en.wikipedia.org/wiki/National_Energy_Program

> Estimates have placed Alberta's losses between $50 billion and $100 billion because of the NEP.[32][33] Alberta still initially enjoyed an economic surplus due to high oil prices, but the surplus was heavily reduced by the NEP, which, in turn, stymied many of Lougheed's policies for economic diversification to reduce Alberta's dependence on the cyclical energy industry, such as the Alberta Heritage Savings Trust Fund, and also left the province with an infrastructure deficit. In particular, the Alberta Heritage Fund was meant to save as much of the earnings during high oil prices to act as a "rainy day" cushion if oil prices collapsed because of the cyclical nature of the oil and gas industry.