Note that Donald Trump, man who would not go into the military, continues to insult and demean the integrity of those who not only served but also went into harm's way and were either captured, wounded, or killed, or all three. Donald Trump hates that simple fact that he knows or suspects he's a coward and his way of dealing with that is to make it as clear as he can make it that such service (the military, especially combat) means little or nothing.

How people can so support such a coward is emblematic of cowardliness inside of they themselves?

There is little truth revealed by humans among humans about the human condition. It is a glaring truth however that this is a hugely intense and deadly competition to survive where deception about whom is a coward and whom is a hero reveals that competition openly in all of its ugliness. If you believe you are not a coward then you must explain to yourself why, if you support Donald Trump, others should not think so....