It's also true that Spullla aren't in a terribly good position to help slaze directly. Indeed, the plan to hit Jowy and try to distract kathlete is probably the most effective thing they could do right now. A more direct intervention would require them to build a pile of galleys to ship troops over.
Now, the fact that they didn't start building said pile of galleys once the Inca war was predicted does mean that they aren't going all out to help slaze. But like novice said, they also don't have an MDP so aren't under the same obligations as HRE is. There's a big difference between not going all-out to help a maybe ally who hasn't provided any notable assistance themselves, versus declining to honor the full spirit of a formal MDP stemming from a long-term relationship.
Now, the fact that they didn't start building said pile of galleys once the Inca war was predicted does mean that they aren't going all out to help slaze. But like novice said, they also don't have an MDP so aren't under the same obligations as HRE is. There's a big difference between not going all-out to help a maybe ally who hasn't provided any notable assistance themselves, versus declining to honor the full spirit of a formal MDP stemming from a long-term relationship.