People despise datacenters for what they represent: a contemptuous capital class who despises humanism, democracy, art and ecology, and is openly working to screw you over and dismantle all that is good in the world. I'm barely exaggerating.

Therefore any argument about them being "not so bad" in the water/noise/energy department is worthless. You can't Spock your way out of it. People feel AI, in its current incarnation (A tool of the oligarchy), only brings negative value to the world. Hence they're opposed to its avatars, like datacenters or the anti-features popping in every app and websites.