You kind of prove my point by you suddenly feeling the compunction to justify your side. Tweets have user names, don't they, you can read? :) I prefer my content to speak for itself rather than turn myself into some sort of celebrity. Anyway, there's nothing you can do about it, if I don't want an avatar it's up to you how long it takes for you to accept that that's my choice and my choice alone. :P Unfollow me if it's really _that_ much of a problem; but in reality, I expect it's not _that_ much of a problem in the first place, which is why I do it.
I won't be bent to do what others demand just because everybody else does, and it's there and begs for attention. If more people took this stance, privacy on the web would be a lot stronger than it is--just because an option or questions is provided, doesn't mean it needs an answer.