Ask them if writing about a complex topic, distilled down to 200-600 words, in English, without a single spelling or grammatical error is mentally demanding.
Now don’t forget you have to convey all the important parts of the story, summarize the entire backstory, and play phone and email tag with people who probably don’t want to sit on the phone with you.
You are also expected to cover every single possible angle on the subject so that the article is accessible to as many people as possible and so that people don’t get mad for neglecting their pet angle or conspiracy theory.
You have to publish your final work, source code and all, to the entire world. A world where a large group of anonymous, mean, vindictive, and horrible people will attack you for the smallest perceived slight to their world view, a personal grudge against you specifically, or for no reason at all.
You have 30 minutes, maybe. Go.
When you get done, do this 3-5 more times today (if you’re lucky). Repeat this every single day of the week.
Ask them if writing a small 100 page novel in English without a single spelling or grammatical error is mentally demanding. Further explain to them that this novel is actually someone else’s story that you have to write as they explain it to you. That person only speaks Chinese (luckily you are bilingual), so you have to translate it from Chinese to English as you go. Then to top it off, the person isn’t exactly sure what the story they want is, so they can only help you get it right by informing you when you have done it wrong from their vague descriptions. You have to complete this in 3 days. (In rare DailyWTF stories: Your boss insists on helping, despite being semi-illiterate) Now is it demanding?
Not saying programming isn’t demanding, I do it everyday(!), but people like to trot this kind of stuff out like no one else has a difficult job; so I bring perspective to what I know ;)