I know what you mean. It's not a perfect system, nor are they complete lists- they pick the worst (to avoid) & the best (to relax about) I guess-?
With the "clean 15"- sometimes chosen because insects don't like them (ie. broccoli), so pesticides aren't much needed. Good to know, right? Or they're chosen because the peels aren't eaten & protect the part that is- like with avocado & pineapples.
The "dirty dozen" often have soft skins that ARE eaten (tomatoes etc) or lots of crevices that trap pesticides where it's hard to wash off (ie. strawberry seeds, greens, peaches, etc).
This article went way beyond the original question, but it's good to consider anyway- & for anyone keeping bearded dragons, for example, they eat many things on the lists.