The reason that someone said the band's Instagram page isn't a valid source for information about the band is because of the rules about self-published sources.

The reason that someone said the band's Instagram page isn't a valid source for information about the band is because of the rules about self-published sources. The rules were patched at some point with a narrow exception, to allow sources for things like a band listing their own releases (see https://en.wikipedia.org/w/index.php?title=Wikipedia:ABOUTSELF https://en.wikipedia.org/w/index.php?title=Wikipedia:ABOUTSE... ) but it's easy for rules lawyers to insist that that patch doesn't apply. And people with OCD really don't like narrow exceptions.