They don't ID themselves but online their IPs do all the work.
Out of all those folks who used the voluntary DDoS application, probably only a handful used it behind a proxy, and even fewer behind a proxy that actually does its job, and even fewer than that behind a proxy that does it's job properly by using such screwed up routes you'll never trace it back.
Most of them who claimed they used a proxy probably just wrote the proxy info on their internet options but forgot that it has no effect except on your browsers and certain apps.
I'd be participating too if it wasn't for that, using a proxy for DDoS is pointless since you'll pretty much be DDoSing the proxy in the process.
I was just trying to dispell the belief that Anonymous is some sort of organized group.
Because its just you and I, every day people, just jumping in when we feel riled up enough.