There are severe constraints on the questions/answers that can appear within the tour: short, no images, no complex formatting, two answers, an answer has a comment, has certain score, etc... The default unicorns/daisies example remains on many sites mostly because there are no eligible examples there yet. Some sites find that their expectations of answers are pretty much opposite of what the Tour expects.
The query for possible examples comes up empty on Health, so the default example is here to stay for a while.
(And no, it's not copied from Gardening & Landscaping because unicorns are off-topic there.)
I wrote a targeted question to address our unicorn problem:
Len() 395, no links no formatting. Even got two sources in to show researched. I don't think I can be the one to answer the question looking at the search quarry, so someone else needs to squeeze out an answer that meets the same guidelines.