Just because something isn't trustworthy doesn't mean you shouldn't use it. If people only worked with the things that they trust, humanity would not have progresses to where it is now. A heap of stuff out there today is self-published, and even with texts that are actually published and edited by others, there's always inherent bias that makes it unobjective and 'untrustworthy'. As long as you're aware of this, there are ways around it (sizing it up to other sources, alternative arguments, etc).