Because posting something that you do not hold the copyright to or have been given permission to post by the copyright owner is considered in many countries to be 'wrong'.
Subscriptions cost money, an open posting would then be free to all that came across it depriving the rightful owner of income derived from property that he/she/they own. I also think you're assuming that a 'subscriber' once they have the document would have the right to post the material legally or do whatever they want with that document (hint: they do not, see first response)
Again, your statement is not terribly relevant, but I'll point out that those 'many researchers' most likely signed off on providing work that would then be copyrighted by IEEE.
I would like the forum admins to reconsider this issue if possible
this is probably best summarized on wikipedia: Institute of Electrical and Electronics Engineers - Wikipedia, the free encyclopedia . In short -- IEEE has the copyright, but allows the authors to republish the papers on their own personal websites. This is detailed at ieee.org in the "author version faq". As of 2011, authors may publish their original work on their sites, but cannot use the version that is actually published if it is different (eg, for formatting purposes). Furthermore, authors (and possibly others) can make a request in writing to republish the work on other websites.
Now edaboard has gone one step further and tries to prevent request of any IEEE papers -- including requests for IEEE papers that are located at the author's (or associated company's) website. This portion might be reconsidered as there wouldn't be legal issues with posting a link to the original author's website. It is potentially difficult to enforce though.
The posted thread "do not post IEEE papers on this site" is also incorrect -- authors do not appear to be able to give 3rd parties the right to republish the works.
Now edaboard has gone one step further and tries to prevent request of any IEEE papers -- including requests for IEEE papers that are located at the author's (or associated company's) website. This portion might be reconsidered as there wouldn't be legal issues with posting a link to the original author's website. It is potentially difficult to enforce though.
This is not true. EDA board will allow links to IEEE papers that are hosted on the author's web site. Provided it is posted as a link to the site and not actually loaded onto EDAboard it makes it easy to see that the paper is freely available to the public. There are examples of this on EDAboard and it is perfectly acceptable. However, most IEEE papers are not available in that way.