Sure they can stop it. Down votes, etc. Anything else is censorship. That is anathema to Steemit.
They could also just challenge it with REASON, CRITICAL THINKING, and PROOF/EVIDENCE which is something someone who claims to teach "Critical Thinking" should know.
I often see you spreading what I would call fake news. Not always, but sometimes. It often comes with someone passing off opinion as fact.
I look forward to your Critical Thinking series... I believe that will be interesting.