I think context is certainly important for this one. As pointed out, a kids' show (or a panto especially, I'd imagine) would be perfectly appropriate for booing the villain. In a typical theatre production, booing would hopefully be a great sign of respect, but if there is a malice to it (or if it is hideously divorced from the perception of quality) then it is disgraceful.
Were they standing and booing? That would be a helpful clarification.
Words don't deserve that kind of malarkey. They're innocent, neutral, precise, standing for this, describing that, meaning the other, so if you look after them you can build bridges across incomprehension and chaos. But when they get their corners knocked off, they're no good anymore…I don't think writers are sacred, but words are. They deserve respect. If you get the right ones in the right order, you can nudge the world a little.