This is not so obvious. This is one of the possible points of view, of course.
"He had tons of proof of that"
For example? I'm not sure other countries stamp a reason for entry like the US, it's usually an entry stamp for anything and that's it.
I'm also sympathetic to the author, but he was extremely naive. The border control doesn't want to hear about nice food or nice wildlife or other blah blah blah. Direct and cooled down answers will do. "On Vacation" is fine.
It's clear his answers (and passport stamps) rang a ton of bells.
This is a horrible way to greet people to come visit and spend money in your country.
My experiences traveling abroad are that most of the other countries have agents that don't make you feel like you are a burden or threat. Imagine actually feeling welcomed when you visit a lush vacation spot.
Depending on the details, yes, it's better, like, "oh, I transited through Malaysia when leaving Singapore"
But remember "anything you say can and will be used against you", so don't go into details unless needed.
And to be honest, someone saying they traveled there because of the Botany, they're either a plant expert or this can be felt as they're hiding something.
Sorry, but it sounds like this guy is a bit of an idiot who didn't help his case, even if the border patrol was overly critical. Trust me, I'm no fan of the TSA or their "SPOT" nonsense, but if I said the things he said, I would expect to get denied just out of spite.
You don't talk to police like you talk to a friend -- you keep the scope of the conversation limited to the question asked. You don't introduce the topic of Al-Qaeda. You don't go into political/religous discussions. Once you do that, you're putting the border agent/cop in a position where he needs to apply subjective judgement. You avoid that by not inserting unrelated noise into the conversation.
This isn't a US issue -- it's a clueless person issue.
It's an issue everywhere there are cops and politics. Every country has some goofy immigration thing to deal with. If you travel the world and are ignorant of the countries you visit, you'll run into trouble.
For example: Canada is probably one of the most chilled-out countries in the world. Nice place, friendly people, no kafka-factor -- Unless you're travelling with a party of people, and somebody was convicted of DWI a decade ago. That individual cannot enter Canada without a visa. Kind of sucks when you're in a car trying to cross one of the smaller St. Lawrence river crossings -- you're stuck in the middle of nowhere.
This part, like the whole story, was a miscommunication. A better answer would be something like "Well I only have Jewish ancestry from one grandparent so I didn't think that would be a problem".
So, yes, he was completely right to deny being Jewish.
Not being familiar with religious customs is not a crime, but then you shouldn't use your ignorance to adjudicate a case.
[1] "Loh"/"Lohe" is an old German word for wood/forest. See also the many German place names containing "loh(e)", such as Gütersloh or Dortmund-Loh.
In reality, he doesn't think of himself as a Jew nor does anybody else, except the jokers that the US federal government apparently hires for these kinds of jobs (and that only after him volunteering that information), so there's no reason for him to have any fears that he might be exposed to antisemitic reactions. How would a hypothetical al Qaeda agent even learn that he has a Jewish grandfather?
Somebody's trying really hard to find a justification for stupid behavior by US agents that doesn't meet any evidentiary standards other than cover-your-ass paranoia.
I actually think it's ridiculous, and sad...
No kidding. Volunteering that he was in Al Qaeda territory... to take pictures of plants. Saying he's a nihilist. Suggesting that the levees in New Orleans might break again while he's visiting. Having Jewish ancestry, but denying being Jewish because not religious.
Also appears he was also traveling alone to many of these places, without any business reason. Entering the US through Canada without having business in Canada sounds like somebody trying to come in a back door, and being nervous to boot.
Even from this one side of the story I'd say the border patrol did their job just fine. I wouldn't have let him into the country in that story.