What's with the weird like, hostility in this post? lol
You say a few times in this post (and the other one) that you "logically get" this, but you don't. Your confusion is evidence enough that you're not quite at a level of understanding on this topic.
Percentages confuse a lot of people for some reason. Look at the numbers and read the writing in the calculator tool:
\- If I purchased an item in 2022 for $1, in 1972 that same item cost $0.14
Do you see how that is an 86% decrease? $1 -> 100c, 100c - 14c = 86c. Hell, in this example, we're even using the original meaning of the word percent... per cent.
Similarly, working the other way around, 14c(x) = 86c -> x = 86c/14c -> \~6.14.