When the source is not an authority, when nothing the source says is verifiable, and when you have a duty to perform due diligence in regards to what you report to your customers as fact? Yes, it's their fault.

Umm...yes? Especially in journalism. This isn't about morality, it's about doing one's job and performing due diligence before believing and propagating a freaking anonymous social media comment as fact. If you are reporting things to people through a channel that is supposed to contain accurate and reliable information, it is up to you to uphold that standard, not the source you are drawing from.