Until you have something delivered to your real address, or exchange bitcoins with a financial account in your real name.
With careful precautions, Bitcoin can, I'm sure, be used anonymously. (Mine the coins yourself, connect to the network using TOR, never use your computer for anything else, be paranoid, never pay for a transaction that could be linked to you, etc).
By this argument, credit cards can be used anonymously too. But everyone isn't going around saying that credit cards are anonymous.
If, sometime in future, Bitcoin happened to be commonly used for online commerce, by casual, semi technical users, then, with the system as its currently implemented in clients, most of most peoples transactions are going to be very obviously linked to other transactions that are linked to their real identities.
If, as the implementation currently stands, casual users were doing their Amazon.com shopping using Bitcoin, Bitcoin probably wouldn't look very anonymous to Amazon at all.
I can only guess how anonymous it looks to Mt Gox.
Now, if you google for it, you will find people out there that are very careful about their privacy, and so go through great lengths to acquire and use credit cards that are not bound to their identity.
I can't speculate why they do this. My point is really that you wouldn't say 'the credit card system is anonymous' even though it can, with great care, probably be used anonymously.
Equally, people shouldn't say 'Bitcoin is anonymous', if the case is that it can be anonymous if used with care, but when used casually, it also leaves information that can be used to link user accounts. People should not think of it like cash.