That would be somewhat similar to regulating P2P nodes, is it not? If your node receives and relay a banned transaction, they take you to jail?

When the pool no longer operates in a centralized manner they become just a pooling service, just like a bus driver, if someone carries something illegal with them on the bus -- the bus driver can't be held responsible in the same manner as if they found those illegal stuff in his pocket.

So I run a pool service which I have no control over, how can I be responsible for what happens inside? Similar to the bus driver analogy, the worst would be shutting down the bus service or the pool.

But when you are the owner, and the operator of the pool, you are at a greater risk, because now, not only that you facilitate illegal transaction a byproduct, you intentionally do so.

It is a lot easier to regulate a pool that create their own blocks vs pools who work as a medium between miners, it's also eaeir to regulate centralized exchanges and force them to ban or even seize funds of certain addresses, but it is nowhere near easy to regulate bitcoin nodes.

Obviously, it's not impossible, it just a lot harder.