Because when there's a snowstorm and my flight is cancelled or delayed, the AC concierge will either get me and my whole family rerouted, or hold the next plane just for us, or perform some other miracle, or at least book us a hotel with no hassle or queue (as they always do; these people are great). I also get first change free now on Aeroplan reward flights, which is actually very very useful, booking this far in advance. (Probably about half the time I end up making some change to my departure or return date.)

So, if these benefits are available on Rouge, then I'm inclined to book it. But if these benefits aren't available to Rouge fliers anyways, and are only available on flights operated by Air Canada, then yes, I'll certainly book UA, to get more space, lower charges (and potentially, yes, partly as a matter of principle).

Does that explain my question?

The ideological anti-rouge arguments are somewhat related, but really for discussion in another forum. Anyways, I hardly think my reward booking boycott is going to sabotage Rouge's future.