If I'm a Trump supporter who sees a fake story about how Hillary's email are proof of treason why would I did into it? It tells me exactly what I want to hear.

This gets even easier if you are misleading and manipulating facts rather than outright making them up. The pope endorsed trump sounds immediately made up, and has nothing to back it up. Hillary conspired to keep drug prices high, when "backed up" by emails is easier to believe. If I already believe she's corrupt then why would I doubt more evidence.