It was made VERY clear, that the mining would destabilize the entire planet.

I have seen also libs praising the old man who was against "violent protests" because its an imperial trap and that it should be a lesson to "PSL idiots". Like Krennic basically made that conference to enforce "yeah we are going to genocide ghorman if we dont find an synthetic alternative". The death of millions of ghormans (remember it was only 800k who were in the direct way of the mining operation) was already pre-planned, they were just crafting a reason.

No matter how civil the ghor were, they are lambs to the slaughter. Cassian vs Luthen's fight was about that, Both didnt know that Ghorman was lost either way really, yes, but thematically it was about using that situation to accentuate discontent in the imperial core vs trying to help ghormans survive (which was futile).