Can we take this out of being just about Trump?
By the way, I was a former registered Republican (loved Governor Kean, not Christie).
The Republican media (from Rush to Hannity) have spent decades cultivating an insult comedy style (think of Feminazis per Rush). They also crafted a very simplistic us/them narrative of flag waiving real Americans vs soft, latte drinking, community organizing liberals who have ruined America. The MSM crafts no such narrative to oppose the right.
Trump may have been the ideal person to weaponize the GOP culture but GOP voters had already been groomed. And at campaigns (remember McCain trying to defend Obama) the GOP base was already ready to believe the worst about Obama (or whoever ran).
For example, HRC was perhaps as qualified a candidate as ever in our history, but she was demonized through the Benghazi hearings, which had little to do with fact finding but a lot to do with creating a future campaign narrative.
So the environment of self serving GOP lies was ready and Trump simply was the right man to use the system to his advantage. Sadly, the template is now ready to go, and the GOP base eats up the appeals to violence.
Just as conservatives in Germany thought they could control Hitler, so the GOP thought it could use Trump. But now we see the Trump-ism is the GOP.
And almost everyone who matters is going along.