This is sort of a "Prompting 101" level concept - indicate clearly the tone of the reply that you'd like. I disagree that this belongs in a system prompt or default user preferences, and even if you want to put it in yours, you don't need this long preamble as if you're "teaching" the model how the world works - it's just hints to give it the right tone, you can get the same results with just three words in your raw prompt.
I tried the same prompt, and I simply added to the end of it "Prioritize truth over comfort" and got a very similar response to the "improved" answer in the article: https://chatgpt.com/share/68efea3d-2e88-8011-b964-243002db34...
This is sort of a "Prompting 101" level concept - indicate clearly the tone of the reply that you'd like. I disagree that this belongs in a system prompt or default user preferences, and even if you want to put it in yours, you don't need this long preamble as if you're "teaching" the model how the world works - it's just hints to give it the right tone, you can get the same results with just three words in your raw prompt.