And TDD is NOT AN INTRODUCTORY LEVEL CONCEPT. Its what you use after you have a grasp of all the basics. The kata is utterly innapropriate for 8kyu. So yes the argument can easily be made that its good to encourage TDD and showcase reasons its a good practice. That same argument makes this 6kyu and not 8

No. If you think it needs marked as spoiler then fine. But that solution is completely valid and is at least using ACTUAL PROGRAMMING SKILLS even if it avoid the intention of a kata. Reading through the loaded javascript on the webpage to understand limitations requires a non trivial amount of knowledge. Probably an amount that would deserve a 3kyu rating maybe?

THIS kata is still trash at an 8kyu rating.

If you want to solve it with code instead of math then it would be a 6kyu equivalent problem. The description (that you quoted) clearly says that is not the expected solution. So either rate it at 5-6kyu for its knowledge requirements or get rid of it.

Putting it at 8kyu serves no purpose other than to demoralize ACTUAL coding beginners. That makes this trash

No you dont because there are TONS of patterns in the given dataset. No one of the patterns has a reason to stand out any more than the others. This kata is just trash. The fact it uses a MATH (not coding) trick that is very popular with lots of parlor tricks is beside the point. Many people will know the trick. But people who didnt will learn nothing about CODING by doing this

This kata is complete trash and has no business existing on this site since its solution has nothing to do with coding.

Any coding skill you could have possibly practiced while doing this kata, you could have improved on doing a kata that was appropriate.

This is complete trash as a kata. It has nothing to do with introductory javascript (which is what anything 8kyu should be) and it doesnt even have to do with logical thinking as 8kyu is targetted to the people who dont know what is possible.

This is just random and thus pointless.