Despite the many protest in the letter from the author regarding the degradation of Buddhism in general and especially in Sri Lanka, I am still waiting to see any reproduction of facts and evidences to support the authors assertion. Which parts of the articles were defamatory to Buddhism or Sinhala Buddhism? If so, why are they defamatory and which scriptural reference in the canons or even which practice in the buddhadhamma supports the view that they are defamatory?

We often forget that even during Buddha's time, there are a lot of criticism and wrong understand of the dhamma. But did the Buddha simply brush them off as defamatory or ask the followers not to question his teachings and to shut up and just listen?
Certainly not. In fact, it's been shown over and over again in the scriptures that the Buddha would take pains to explain logically (not just based on blind faith and magical charisma) why certain views were wrong or certain understand is incorrect. Certainly if the author felt that wrong views and incorrect understanding were being publish, the author should explain logically with facts and evidences why those are wrong and incorrect.

It is by the actions of the Sangha (monks and nuns) and the lay community that Buddhism is safeguarded. When the actions involves dogma, blind faith, violence, hatred, anger, bigotry, discrimination, self-interest, intolerance and whole array of unwholesome activities, then this will bring about detrimental results to Buddhism. If those actions involves free enquiry, understanding, tolerance, peace, love, compassion, kindness, letting go, equanimity and a whole array of wholesome activates, then this will bring about the safeguarding of Buddhism.

I am sure that the readers themselves can judge by the actions of the individuals and the monastic, which are wholesome and which are unwholesome activities as understood in the context of the Buddhadhamma.