And that's a fine standard to maintain when you're writing an academic paper.

When you are instead putting together a museum exhibition intended for the general public, and you observe over and over again that they will interpret your work as representing what the statues actually looked like, it is irresponsible to keep giving them that impression.

It's not an either/or question. They could do some of the statues with just the pure archaeological approach of only using the paints they found in the crevices, and do others in a layered approach that is more speculative but probably closer to how they actually looked. If they did that, this article would not be necessary.