How does anyone know a post has been approved or just been posted? There is no difference! Again, people are trying to make this about something it isn't.
Look at it this way:
Allow people to post in a public forum, without having it approved by a moderator first?! How can we possibly allow that? Someone might post a dirty word! Or offer a SWU where they aren't supposed to! The moderators will be overwhelmed! Civilization will break down! What if someone posts claiming to be someone else? WHAT IF SOMEONE POSTS A LINK TO A SITE WITH INAPPROPRIATE CONTENT?
JFC people! An avatar, like an inline image, is just content. We (i.e., the site community as a whole) deal with content every day and society hasn't collapsed. I seriously, seriously doubt there will be a rush to post naughty avatar photos. Certainly nothing beyond the occasional trolls, spammers, and hotheads we deal with every day anyway.
I really don't understand the freak-out some are having about this. You don't want to look at avatars? Fine. You have the option to disable them. So that leaves the other big objection: it's too much work. And I'm calling BS on that.