A presidential election isn’t going to be decided by my vote. In the infinitesimally small probability possibility that it seemed to come down to my one vote, there would be a contested recount with a judicial decision determining.
So it is irrational, or at least highly unreasonable, to vote as if my choice will determine the outcome at the state or national level.
My vote is instead an expression of opinion as to who should win.
Also, if voters think they were manipulated into voting for Hillary by some kind of Democratic Operation Chaos, they might rebel against the manipulation by voting for Trump.
For those who don’t buy this, it’s what Grumman said in #15.