These tweets are the voices in Trump's head.
Trump seems to me to be a person who had to create a false personality in order to survive his childhood (his brother died an alcoholic). Eventually, the false personality took over and buried the person that Trump was. But I'd like to think that that person is fighting back, in the form of tweets addressed to the created Trump.
Because, @Chae, as you said, every one of those tweets actually applies to Trump himself.
Sad. Pathetic, to quote someone.
I find it interesting that Trump first found political fame in doubting Obama's authenticity and birthright, as if that is the worst thing that he can imagine.