What is the risk of keeping that dead code? Right now the risk of removeing the dead code is more people running knots.

Because it creates bad incentives, if relaying OP_RETURN transactions is hard, people who want to inscript will bloat your UTXO set. You will be able to do nothing about it, whereas now you ignore everything after OP_RETURN even if it's part of the block.

Lol, dead code is when a function is called and has a deprecated feature. This is a feature that still gets called to define the standardness of a transaction. Dead code...pfft repeat things you hear some more, dude.