I'm not sure this particular example fits the "sarcastic" angle. I believe a more charitable interpretation is possible:
> HH: I’ve got two more questions. Last night, you said the President was the founder of ISIS. I know what you meant. You meant that he created the vacuum, he lost the peace.
You could infer from this that HH is trying to limit the President's culpability - a difference of "happened on my watch" vs "I am directly responsible".
> DT: No, I meant he’s the founder of ISIS. I do. He was the most valuable player. I give him the most valuable player award. I give her, too, by the way, Hillary Clinton.
Perhaps DT's objection is over the implication from HH's statement, rather than to be taken literally. He goes on to temper his statement - the President had a "very important role", etc. Outside of this context, DT's objection is not very coherent, but that's the nature of a (presumably) unscripted, antagonistic interview. Case in point, HH blunders in their retort:
> HH: But he’s not sympathetic to them. He hates them. He’s trying to kill them.
This objection is moving the goalposts. You can be a founder of something and hate it - the founder can be displaced, the "something" can change course, etc. You can tell HH is reading into what DT is saying - HH seems to think that DT is pushing a "the President is an ISIS sympathizer" narrative, which isn't at all indicated by DT's words, and he immediately disagrees:
> DT: I don’t care. He was the founder.
In thinking about this interview and how I just overanalyzed it, I reached a frustrating impasse. It would certainly be great if DT had the eloquence of Obama, and his statements were well-crafted and not so open to interpretation. On the other hand, relying too much on the eloquence of politicians leads you into a hole of "empty talk" - they say a lot of words, take no positions and after analyzing their response you realize it lacks any substance.
DT does not conform to the standard mold of a politician, so I think it's difficult to try and analyze him through it. He will eventually become President, and be forced to make decisions - actions are much easier to evaluate than words.