GINGER GM not allowed into the USA

That is by no means the worst thing that could have happened to him. I hate to say this about my country, but coming here is a dicey proposition these days, look what happened to the young British security consultant who stopped the WannaCry extortion scheme, then came to Las Vegas to address a convention. You can still address a convention remotely from the safety of your own country. Of course, England doesn't have anything like Las Vegas, I'm sure they have gambling and liquor and hookers too, just not all in the same place available 24 hours/day.
PC stuff is so weird. If he had been blocked in any other country for not having his papers, it would have been shrugged off as his fault. If I, a nobody, had been blocked for not having my papers to go to Europe, no one would care. But because its the USA, the guy failing to have his papers is somehow the fault of the USA and somehow leads to comments of bigotry. Bigotry is sending him to a holding cell and giving him a hoopajoo scan for being foreign. Bigotry is stopping the flight because someone has a beard and a turban. That crap happens, and we can engage some critical thinking when it does. But some guy that left his passport at home or whatever ... everyone who does that gets the same treatment. I can't even travel around INSIDE the USA via plane without my ID much less come into it from another country. ID is required because there exist idiots (who are, by the way, bigots & racists ) who hijack planes or blow stuff up for their "cause". There is nothing to see here. Its a non-event. Next time, bring the paperwork.

Visas - Easier to comprehend than the rule on when the time runs out.
"Why are you coming to the US?"
Tourist
Says here you're competing for prize money in a chess tournament, and, possibly you are being compensated for your appearance at the event by the organizers.
Ummmmmm, is that a problem?
From Reddit:
If you come to the USA for purely tourist purposes, it's fairly easy to get a tourist visa (or ESTA). But if you are coming in order to earn money in any way, you must have a different visa.
For chess players, if you're coming to compete only for prize-money, then a B1 visa is likely the right visa to get (it's cheaper, and more likely to be granted).
For the best chess players, who are looking to earn more than prize-money, a P1-A visa, or an O1 visa, might be the right visa. But that has to be applied for months ahead of time, and the application needs careful documentation to be included. Turning up at the border with an inadequate visa is always going to be a problem.
This is mot a difficulty with the USA specifically, it's quite common across the world.