Well the Jerrys are also notorious for getting in over their heads. One of them got destroyed by a swarm of crawlers in Shrakrahmi.
There's no doubt in my mind they're in it for the gil, but they're just a bit too overzealous for their own good sometimes, and that Oztroja incident is a good example. They remember who helps them. A person named Sephrioth is apparently in good standing with at least one of them as he was buffing and curing one of them as he hunted in Pashhow awhile back. So it makes me think that the training wasn't intentional. They're aggressive, but MPK seems a bit extreme even for them.
...wow I think I study them a bit too much.