IRC is inherently non-private because anybody can join and then do whatever with what they saw.
IRC isn't really unencrypted in transit though, you can connect via SSL (most people do so, probably) and there are channel modes on some networks that prevent people from joining if they aren't using SSL to connect.
You can also encrypt messages yourself and then send those on top of the IRC protocol.
As for anonymity, most IRC networks allow you to use a cloak to hide your IP (requires user registration, which would require one email interaction), some IRC networks hide your IP (or parts of the reverse DNS) and some IRC networks allow you to join using Tor.
I also encourage the use of proxy servers and/or vpns(preferably not as a service!) when using irc on the wild world of the web. In addition to cloaking, and everything else you mentioned.
IRC isn't really unencrypted in transit though, you can connect via SSL (most people do so, probably) and there are channel modes on some networks that prevent people from joining if they aren't using SSL to connect.
You can also encrypt messages yourself and then send those on top of the IRC protocol.
As for anonymity, most IRC networks allow you to use a cloak to hide your IP (requires user registration, which would require one email interaction), some IRC networks hide your IP (or parts of the reverse DNS) and some IRC networks allow you to join using Tor.