This is talking about a committed bloom filter. Not a committed UTXO set.

I read the following comment to mean it requires the UTXO commitments. Otherwise I'm not sure how you prove absence of withholding with just current block structures+an extra filter included in the block:

but with the bloom commitment (and UTXO trie organised commitment) he
can verify that the positive hits are correct via the merkle path, and
that the false positives are not being wrongly withheld by obtaining
merkle path proof that they are not in the trie