In the long term, you are absolutely right. It's perfectly reasonable for people to want to have a #gentoo or #ubuntu or whatever, channel on Freenode. I also think it's reasonable for projects to have some time to disambiguate where the official one is.
For my project specifically, our IRC traffic is very low - there are a dozen or so lurkers and then people who come in briefly after seeing the channel mentioned on our website/docs, to ask questions. I've updated all of those things, but I want to leave a message in the channel topic for people who already have it in their IRC client, to see, so they don't think I've completely abandoned them.
My solution for now is to have the topic say that it's an unofficial channel in which people are welcome to discuss things, and then a URL to the section of our website that details how to get help, which links to Libera :)
For my project specifically, our IRC traffic is very low - there are a dozen or so lurkers and then people who come in briefly after seeing the channel mentioned on our website/docs, to ask questions. I've updated all of those things, but I want to leave a message in the channel topic for people who already have it in their IRC client, to see, so they don't think I've completely abandoned them.
My solution for now is to have the topic say that it's an unofficial channel in which people are welcome to discuss things, and then a URL to the section of our website that details how to get help, which links to Libera :)