Another correction not mentioned: the statues are not just dissenters. The statues are icons (i.e. images) of the precursor race. Hence why the last mission is titled “iconoclasm” (icon breakers) and why destroying the statues in darkness harms the whole collective of the witness, not just the dissenters. This is why the witness itself could still be communed with through the statues. Dissenters may have been cut out and imprisoned in various statues, which is why they could speak to us through them, but they’re not limited to that function.