Oh come now. The reason you shouldn't have to crawl inside his head is that you can engage in discussion to learn what he thinks.
If the issue is a dispute between what I believe Trump is saying and what you believe Trump is saying, we could have a discussion where we break it down and identify what parts we share and what parts we don't share, and why.
For example, we could start by agreeing that Trump is opposed to immigration. You could claim that this is racist. I would suspect this is a deeply held prejudice so I would just dispute it and move on. I would claim that "Building a Wall" is just a rhetorical device to focus people's attention on the more abstract and tedious problem of an insecure border. You could point out how Trump or his surrogates have used various examples of actual border walls in other parts of the world, which would lend credibility it being a real promise, not mere rhetoric. We'd both have learned something. And so on.
Alternately, you could just go opposite direction and just start throwing around vague, obsolete terms like Fascism and the discussion would go nowhere.
But of course, the bigger problem here is that I'm not here to convince you not to support Donald Trump. I hope you won't. But if you do: fine. Sam Altman does not agree with you. He likens Trump to a dictator. If you're a Trump supporter, you are not the audience to whom my argument is addressed.