People talk about avoiding the hypothesis, but in these cases the hypothesis should be avoided.

Harmful truths are not extreme hypotheticals, they're a commonly recognized part of everyday existence.

• You don't show photographs of your poop to a person who is eating - it would be harmful to the eaters' appetite.
• You don't repeat to your children every little grievance you ever had with their other parent - it might be harmful to them.
• You don't need to tell your child that they're NOT your favourite child either.

Knowledge tends to be useful, but there's no law in the universe that forces it to be always beneficial to you. You've not indicated any reason that it is so obliged to be in every single scenario.