Especially someone who stands to gain if they only need to get cozy with two email providers to deliver their spam.
(Blog author) runs the email infrastructure measurement project at Live Direct Marketing
Google offers "mail merge in Gmail to send personalized email campaigns, newsletters, and announcements to a wide audience." [1]
Based on how much @gmail.com spam I used get within GMail I can only assume they treat mail from their internal accounts much more favourably then us dirty self hosters.