I personally feel no responsibility or inclination to provide feedback on personal custom threads. I'm here for collaboration and enjoy group projects that are give and take. I have no real incentive to get involved in personal custom threads of other people and no real interest in what they're doing. To me, personal custom threads, where it's about a singular designer rather than collaboration, are much more of an all take, no give situation.
That said, I realize at their best that personal custom threads do inspire collaboration and that's when customs and the process of customizing reaches its full potential. But why try to reenact that in a space that's not naturally inclined towards it when it's so easy to just do collaborative design in a project where that's the established approach?
As a designer, I also never want to do a solo act again. I've been to the Promised Land and I'm not going back.