No "Discovered It" Logs Allowed!

I was in the vicinity of one of my seldom-visited caches yesterday and stopped by for a maintenance visit. I noticed a really nice geocoin had been sitting there since the cache was last found nine months ago, so I jotted down the number to log a "Discovered It" log later (I don't make it a practice to grab nice trackable items from my own geocaches, but rather let others enjoy a pleasant surprise when they visit them).

I thought the coin owner would appreciate some news that their coin is still there, and I wanted another cool coin icon on my profile page. I placed my "Discovered It" log on the geocoin, only to have it deleted by the cache owner with no explanation. When I emailed the cache owner, he referred me to the geocoin's page, where it says, "Discovered it" logs will be ruthlessly deleted without warning or exception."

Wow, I never saw that kind of rule before, and I'm still trying to understand the logic and motivation behind it...