And this, ladies and gentlemen, is a good example of how certain people come to believe in conspiracy theories.

They are faced with a seemingly overwhelming argument that destroys some fictional narrative they chose in their head, probably because they misremember or misunderstood some basic fact behind that narrative in the past (like not listening to a thing during math and sciences classes).

Re-evaluation of all the facts in light of new information would be too taxing, and probably lead to an undesirable outcome even if completed successfully (like realising they were wrong, and possibly start questioning themselves), so a different strategy is employed.

This consists of cherry picking a very minute aspect of a bigger picture (here, that trump puts the medal in his pocket) and spin a whole narrative around it.

This works surprisingly well, at least for them, since their brain has either forgotten the conflicting facts, or outright fails to recognise their glaring ignorance about all other possibilities to explain that minute aspect differently (like the fact that the guy handing over the medal to trump is talking to him, in what looks very much like the act of gifting him the medal).

Where this unfortunately breaks down is when other people, not so reality-impared, challenge them by pointing out the glaring factual omissions.

This is usually seen as a personal attack, like they're being called out individually and being called unpleasant things (which can be usually the case), and will respond by questioning the other person's character, intelligence and/or intentions.

Oh, and downvoting.