For most algorithms (neural networks, neighbour methods, linear methods, svm) I would agree, but something like a small decision tree could have enough human input to show that there was "substantial human input" compared to the computer-generated part. Perhaps the author could argue that they tried a few different depths or loss functions to achieve a particular aesthetic result, or they manually pruned the tree afterwards for some purpose.

Also, a graphical manifestation of that decision tree would be copyrightable, because there are many human-made choices in its display, particularly if it is designed as a tool for human beings to use to perform inferences. (Again, there's probably no equivalent copyrightable graphical manifestation in other ML techniques, so this wouldn't apply there either.)

But the bulk of your point is true, in all jurisdictions, almost all ML models are not protected by copyright.