Don't underestimate the power of one letter. Someone will read it at Bethel, maybe more than one. The more letters like this they receive, the more time they spend having to read them. Who knows at what point one of these letters will cause someone to wake up, or at least question their beliefs.
Recently I wrote a letter to the Society regarding a pedophile in the congregation. I was disappointed with the response. But after realizing how many people had to read my letter, I felt like maybe it was not such a useless action as I had first thought. I know that 3 circuit overseers and at least 3 or 4 elders read it before it ever got to Patterson. How many letters do they get like mine nowadays? At the very least, it costs them time and money to read or respond, time and money they would rather be using to "promote Kingdom interests".