First off, by default we assume fodder is much weaker than playable characters. And even by the end of the tutorial they're not taken seriously anymore. Then there's the "Marsha" sprout moles which allegedly are masters of the axe but actually just have an axe duct-taped to their body and a really lost expression. The Therese sprout mole also looks like it's struggling a lot. Then there's the "Sprout Mole??" enemy which is made of the strongest parts from the strongest sprout moles and is still just a fodder enemy.
That's not really a species being shown to be weaker than everyone else. They're just a recurring species of enemy, with new versions being able to take out your party throughout most of the game.
Maybe I'm just missing something, because I don't see how that link has them "not being taken seriously", it's just Kel saying they've got the hang of it, and charging in to fight. And like, to be clear, it's not like sprout moles are weak enemies that roll over and die instantly without dealing damage in every area, they're usually on-par with other enemies in those zones. If you consider every non-boss enemy fodder, then fair enough, but I wanted to make it clear, since it kinda sounded like you were saying every other species in the game is portrayed as stronger.