Well, to give the Prudecutor her due, at least she didn't pack the court with fawning follow-ups designed to attribute to her an infinite wit and wisdom which she possesses not. It certainly would have been easy to stack the deck; who could have proved it different? So the Unwanted House Guest turned out to be not quite so sinister as she thought.
But one glaring thing sticks out from the Twincest Follow-Up. Our LW mentions in the follow-up how his brother read the column at breakfast and flipped out when he caught on to the personal nature of the subject matter. One must wonder, therefore, why the flying flip the Prudecutor and her editorial council ran the letter without looking into the situation in the first place.
The LW obviously was familiar with the Prudecutor's column, and it stood to reason as highly probable that the twin was as well. As their circle had a reasonable degree of familiarity with them and their lives despite not being in on The Big Secret, it ought not to come as the greatest shock in the world if some of their acquaintance might just happen to be readers of the Prudecutor's column as well. Should such be the case, how possible could it be that any such person would not add up gay twins living together as supposed bachelors and not visibly dating?
As it would not take a team of rocket surgeons to work out the likelihood of discovery, the next thing is to wonder why the Prudecution would run the letter without first checking in with the LW that it would not ruin his life. Now, one could easily claim that there's no obligation to do so. And certainly the Prudecutor's conduct since the letters has been indicative of excessive salivation over the increase in traffic and revenue the letter would bring her way, given its vast superiourity to the legions of dull letters that only made this shine all the brighter. But not to check in first to make sure that both the LW and his brother were okay with the letter being run? Perhaps not necessary, but reasonably described as Heartless.
As for the follow-up itself, the LW comes across as rather the tedious sort, or at least borderline so. I do not blame him for Fitting the Stereotype; some people do, and he at least does not Universalize it the way one sees happening only too often. I just detect a bit of the wrong sort of uberassimilationist strain in the bit about sexual dropping-off being Not Uncommon Among Gay Male Companions and Guess What? Some Straight Couples Too!