For me, once the words "I will deport millions of people quickly from the country, build a massive wall to keep the rats out and ban everyone of a religion from entering the country for an indeterminate amount of times" were uttered from his mouth, that would have been enough for me to say "you know what? This guy is a bloody idiot".
But 'murica it seems! It's hard to not just laugh in the face of people who support him, but laughing at them or pitying them seems to pour fuel on the fire.
Just got to hope common sense prevails.