I think there not being an instant happy ending for all the superpigs is more poignant.

The point is that there's no quick fix that's going to stop all the cruelty, and if Mija and a ragged band of eco-warriors had managed to, say, shut down that factory farm on their own somehow, it would have been doing a disservice to the grim reality of the animal agriculture industry, and glossing over it all, only to leave the viewer with a false sense of contentment and relief.

Cruelty and suffering is deeply ingrained in the system, and only societal and systemic change can alter that.

A clearer message about how wider change could be brought about might have been beneficial, however.