Your daughter needs to define her position. "Fremantle is better than West Coast" can be interpreted in many different ways. You could just take it to mean the current AFL teams. Or the teams over their history. Or the supporters.
If I'd been asked before the RL tenure, it would have been easy. Freo were the dreamers. They'd conjure up magical images. They had Clive. If pedestrian and plodding was your thing, then by all means back WC. If you lacked ego strength and had to support a "successful" club, then go for WC. But if you dreamed of what had never been done and said, "Why not?", then you had to go for Freo.
Post RL, with our jumper gone and the only truly good bit of our song gone, and having moved from our spiritual home, and playing "system" rather than flair, we are a sad shadow of what we were.
Actually, speaking of the old days, your daughter should go creative and borrow Shane's "Boys don't cry" clip. A few minutes of that and most of the kids in the class would support Freo.