It would've been more interesting, to me, at least, if Vaal didn't use explosive rocks, but regular vegetation as fuel. Especially if they'd been able to get inside, at all, or at least hear Spock theorize on how it might've worked. What a shame that little misunderstanding had to be cleared up. I liked it better the "other" way, better ...
But that way makes no sense. There's not enough potential energy in baskets of fruit to do what Vaal is shown to do. Some kind of high-energy yielding material like the rocks (assume it's something like uranium or something) to do what the story requires.
Poor Spock really takes a beating in this episode.
"Poor Spock" has it a infinitely better than the record number of redshirts nailed in this episode!
Look at it this way: if we take this reasoning to its conclusion, then Starfleet would have no right to protect itself from, say, the Borg, because when the Borg assimilate...
Which would be the case if that's how it was applied, but in original
Star Trek it was only used in reference to non-spacegoing cultures. Once they're out their in space they're going to meet other cultures on their own and that's going to have an impact, so at that point they are "peers". But before that the idea is that WE don't go mess with them and change the "natural" development of their culture. That
TNG turned in into crazy "we can save them without them knowing, but we won't" is not germane to
Star Trek unless you want to retcon it,