You TAG people and after a while that's all anyone remembers. Nothing new going on.

"By now, everyone knows assigning nicknames to opponents is Donald Trump’s trademark political strategy, and this week Hillary Clinton got hers. For as long as Trump is in this presidential race, and maybe beyond, Clinton will be, in the minds of some voters, “Crooked Hillary” in the same way that Marco Rubio became “Little Marco” and Ted Cruz has been “Lyin’ Ted.”

Trump doesn’t have to back up those designations with deeper content to make them stick. These insults require no additional information beyond knowing what the names are meant to imply. And the implications here aren’t subtle."
‘Little Marco,’ ‘Lyin’ Ted,’ ‘Crooked Hillary:’ How Donald Trump makes name calling stick - The Washington Post

In doling out these simple nicknames, Trump appeals to that human instinct to categorize and label as a way to have stability and certainty.