Dear Sword,
May peace be with you.
I have perused the link briefly, however I cannot add anything more than what brother Irfan has already said. He has resonated my view on this matter entirely.
The month of 'Ramadan' was known to the contemporaries of the Prophet before Islam was revealed to them. The Quran which remains the earliest historical document of Islam clearly indicates that it did not invent a new name nor introduce a new concept.
Therefore, I would find unwarranted any implicit appeal to secondary sources whether in the ambit of western scholarship or otherwise. It is well appreciated that there remains a dearth of sources in this period and much inferred is usually based on material which is not contemporaneous to the Prophetic ministry or inferences drawn from isolated archaeological data. With respect, this is not comprehensive evidence which would warrant cogent appeal.
Furthermore, given that lunar years are shorter than calendars based on solar years, the month of Ramadan could technically fall into 'cooler' months over the course of the years and decades. Therefore, I would find superfluous any root word analysis in this regards.
It is also highly unlikely that a fundamental practice such as fasting which finds direct support from the Quran and would have been practiced en masse by the new believing community would have become subject to such a large scale conspiracy that would warrant the kind of corruption of the actual month of fasting that is being suggested.
I hope that clarifies my position on this matter, God willing.
Joseph.