Many (many) forums have rules, where if you don't post with a translation you can get a warning or a ban. Agreed, IMSLP is an international forum, but efforts must be made to translate as much as possible. The overwhelming majority of people at the IMSLP speak it. It is not the business of the reader to translate via an online translator; it is the business of the writer. Most countries have English as there second language, although it could be argues that having English as the official language is bias, it benefits of having it as the official language outweigh the negatives.
Furthermore, Vivaldi was not directly asking you to translate; he was asking anyone to translate – for the benefit of these forums.
http://en.wikipedia.org/wiki/English_la ... l_language
So why should anyone spend their time translating all of this?
It benefits the forums to do so.
why is this not sufficient?
It is sufficient, but it is not satisfactory. You merely stated the topic, not a summary. Although, thankyou all the same for providing it!