No offense, but I'm not sure you understand "UTXO" well enough to explain it to others. For starters, UTXO is nothing new, this post is about "committed utxo". As maaku explained, miners need to know that they're mining on top of the valid chain, that's the only way they can know they have the accurate UTXO.
maaku
confirmed that I understood UTXO's SPV+ mode.
Jorge is correct: miners have to know they are building on top of a valid chain, and to do that they need to validate the entire block chain history. The post you linked to endorsed a statement which included this caveat, which your most recent explanation does not.