Knots nodes still pass images and large op_returns through the network, *when they have been mined into the chain*

Many nodes refuse transactions below 1sat/vB, and indeed some miners refuse to include them (e.g. ViaBTC), but there are hundreds of those transactions in most blocks. Big miners are making extra profit through their out-of-band systems, where they make extra money for including transactions.

Filtering them just means that the relay network is less good at predicting the next block.

And that's bad because it means small miners can't stay up to date, and they can't get their blocks quickly accepted by the rest of the network.

The filters don't work at blocking things, their only impact is to harm small miners.

There are subtleties in all the above. Certain kinds of relay filters can work, but it's all about the complex interactions between game theory and technology.

You mentioned "bloating the chain with images and video". I still haven't seen a credible plan - based on expert knowledge of all the issues - for how to keep these out of the chain.