You can make any kind of argument when you go to court. The thing is, you try to put your best arguments forward and hope they stick. However, there's a critical difference in legislative drafting between a “whereas” clause and a principle versus a substantive right.
When you say in the whereas “we want to provide funding to first nations”, that's very different than if you have a section in here that says “the minister shall provide” equitable funding to first nations or equal funding to first nations. That's part of the problem when you're doing legislative drafting. Any of the core commitments—rights that are judicable, that you can actually take to the bank, take to court and sue on, and have enforced and get injunctions and that kind of thing—have to actually be rights-based, not just in the fluff, because principles are, “well, you know, that was our general idea”, but there's nothing that outlines what is the mandatory way in which that would be interpreted.
It would be an argument, but not necessarily a successful one.