Also anyone else notice the little comment which is. We are the good guys. So we can do whatever we want.... I think Brand is letting his hero complex go to his head. As the reason why the Quetz are forbidden from going to the mountain. Probity is due to it being insanely dangerous...As forbidden is a term used to ensure peoples Safety, not just a spiteful rule.
On the one hand, this is the quetz. They
run on spite and greed. The fish rots from the head down, etc. Saida-hime is just the exception that proved the rule with this bunch of nonces.
On the other hand, that "sacred mountain" thing can mean a bunch of different things, and the edict to
NOT GO THERE may well predate Vetra-jou's fall from grace, i.e. it was put into place immediately after the Puppet Wars ended. So Saida-hime... well, she may have a point here. But on the other paw Brand-san may well be right. It's the only good hiding place they
have that's guaranteed to not draw continuous Long Patrols of quetz searching for them.
TL;DR: Brand is helping. Again.