I don't think that allowing child porn on the blockchain is going to prevent child porn being put on the blockchain.

If banning child porn somehow encourages a small minority of pedophiles to try and share child porn well at least we are preventing it.

Once these "garbage bins" you want to fill the park with get trash put into them that trash becomes a permanent feature of the park.

So it's actually the opposite to adding bins to a park, bins exist so that the rubbish inside them can be removed.

A better analogy is that core are adding a public noticeboard to the park where people can post up child porn images and whatever else permanently