Stop spreading your unfounded claims and post proof that there is a difference!
(i am not blindly defending 4gb, because my macbook has 8gb ram and I need 8gb ram!)
You need proof to explain why 8GB of RAM is more beneficial than 4GB of RAM?
Windows requires minimum of 2GB RAM
OSX Requires minimum of 2GB RAM
Let's load something else... oh wait, you're tied up with the minimum requirements of RAM. Whoops!
Yeah you can limp through it, but clearly when you have 2 OS running at the same time like a user who has Parallels or VMware running windows, you're already maxed out just meeting the minimum requirements.
I guess probably not proof enough for you though.
Sources:
http://windows.microsoft.com/en-us/windows7/products/system-requirements
http://support.apple.com/kb/HT5842