Linguistic arguments are kind of pointless, but it's still an attack even if they are just trying to disrupt the system and not steal anything. e.g. a denial-of-service attack.
Various definitions of "attack" are at http://en.wikipedia.org/wiki/Attack_(computing)
It's certainly not an attack on not-bitcoin, so therefore it's an attack on bitcoin.
See, I can say ridiculous things too. Someone using bitcoins didn't follow protocol and as such as scammed out of money. This isn't a bitcoins-protocol issue, this is a people issue.
Note that the other exchanges are up now, very quickly after everyone stopped to check themselves.
I would argue it was an attack on Bitcoin the ecosystem, due to an _oddity_ of Bitcoin the protocol. Bitcoin the idea is still fully alive. The attack worked from within Bitcoin, the network.
The standard client just assumes that the transaction is legit and you can use the remaining coins immediately. But to use these coins the program has to know the ID of the transaction.
But due to the malleability, it's possible that the ID that is generated in your client is not the same ID that is finally added to the blockchain. If you use the original ID and it is changued, then the next transactions will be invalid. So you must wait to see the final ID and use it to create the next transactions.