If you would call Ordinals an attack, then you need to have a reasonable explanation of what the attackers are willing to achieve from it. Is it BSV folks trying to raise fees so that people would move to their chain? But then—there are a few thousand other blockchains out there. What if they move to ETH or something else? So, this has to be a coordinated attack by a few dozen altcoins, which also doesn't make a lot of sense.
But I gave an example, large pools artificially increase block fees.
If the 3 or 4 largest pools on the market align, they can create Ordinals transactions with high fees, knowing that they will get the money from these fees back in the blocks they mine.
Another way is for large pools to create Ordinal transactions, at the same time as reducing their hash, following a difficulty adjustment on the network. The network becomes clogged, generating a greater number of pending transactions in the mempool, which will generate fee increases.
Of course, I'm not saying that this is what's happening. Because it will be difficult to prove, even if it is happening. But these are scenarios, which happen, could be considered an attack on the network, as they were trying to take advantage of a protocol for their own purposes, damaging this entire protocol.