Because the notoriety is their armour.

These releases rely on a massive amount of storage capacity from volunteers to seed these archives as quickly as possible. The more people sharing them, the faster the network grows, and the harder it is for feds to shut it down.

Flashy releases help start the swarm fast, and make the fallout easier to manage as lawyers dont had the leverage of being able to shut down some server to kill the whole thing. Doing it in stealth wouldn’t benefit much, especially with how trivial it would be to source the original archiver anyway.