I am guessing you haven't umpired NCAA or NFHS softball.I appreciate your explanation and taking the time to share past rules and interpretations. It looks like this phantom dirt-rubbing rule, which neither 1-3-6 nor 6-2-2 actually addresses, has been around for a while. Hopefully in the future it will somehow dawn on the powers-that-be that when they write explanations of rules, they should first make sure those rules are well written and actually exist in the rule book. They need look no further than the NCAA softball rules to see how to do a much better job!
The NCAA rule book is so very terrible. Umpiring using college rules is unnecessarily complex on top of dealing with college level games and the 'detail' they include makes things even worse. It is what happens when you let people with no experience of writing rules, write rules. Lots of rules and text to appease specific coaches (*cough* UCLA) or to prevent abuse of loopholes (*cough* Florida) or to address a very rare scenario which all have had unintended consequences.
So much worse than the NFHS book (which is no great publication either).
The worst rulebook ever is the NFL one. That thing is awful - which is why they get into so many stupid things every year.