No dumb insult or copied photo you have downloaded about President Obama makes Trump in any war less of a grandstanding boor with delusions that he is qualified to lead any country.
Barack Obama does not deliberately insult people: on the contrary, he is diplomatic, tactful and polite. Trump picks stupid fights over non issues just to call attention to himself.
Whether or not he thinks John McCain is a hero, or os less a hero because he was captured is not important to anyone on this planet. It is one man's value judgement. The implied idea is that McCain deliberately allowed himself to be shot down, that if he had somehow been more brave, he would have avoided being shot down. And that is just absurd.
Imagining a Trump presidency is easy. On Monday he would insult someone, on Tuesday, friends of the insulted party would demand and apology, and on Wednesday, President Trump would refuse, adding more insults to the apology. Real issues would be ignored, complicated issues like foreign relations and the budget would be swept aside because of Trump's constantly tooting his own horn and saying dumb shit.
And, seriously, we have all heard enough bad hair jokes about The Donald to last every one of all the nine lives of every cat on the continent.