That was actually your best laid plan, to try to encite wizards, who can actually kill other wizards contrary to the long list of "demigods", to kill themselves in a civil war.
With a DC 15, it wouldn't work because many, many, many people could defuse the hate against Wizards you're trying to create. Even CHA 8 wizards are susceptible to make the check 25% of the time without trying (and they'd probably cast Enhance Ability (Eagle's Splendor) before making their public speech to get a success the majority of the time.
Lazy One to crowd: "the Wizard is cooking babies!" (Lazy One then disappear in the shadow, walking to another city)
Crowd: "booo! let's try our town wizard for cooking babies!"
Wizards: (casting Eagle's Splendor): "That's a baseless accusation! I am eating babies RAW!"
Crowd: "ah, ok, sorry, then".