From Sourceforge.net Terms Of Use:
Prohibited PersonsYou represent you are not a person on a list barring you from receiving services under U.S. laws or other applicable jurisdiction, including without limitations, the Denied Persons List and the Entity List, and other lists issued by the U.S. Department of Commerce, Bureau of Industry and Security, detailed at
http://www.bis.doc.gov/complianceandenf ... oCheck.htm (or successor sites thereto). Users residing in countries on the United States Office of Foreign Assets Control sanction list, including Cuba,
Iran, North Korea, Sudan and Syria, may not post Content to, or access Content available through, SourceForge.net.
SOURCEFORGE.NET SITE INFORMATION
IP: 216.34.181.60
IP Location: Cary, United States
Having their servers on U.S. soil, they are under the jurisdiction of U.S. laws. I doubt that Sourceforge people have any personal dislike for people of Iran or of any other banned country.
It's just that
dura lex, sed lex. No one wants to get in trouble with federal dumbass law even if it directly counters the "mission" of the site.
At least Internet has many ways that one can exploit to bypass all these dumb regulations and restrictions.