That sounds like the system working as intended - the newsletter is there to promote your blog, your product, whatever - the point is it's not 1-to-1 human-to-h

That sounds like the system working as intended - the newsletter is there to promote your blog, your product, whatever - the point is it's not 1-to-1 human-to-human email, so flagging it as promotion is appropriate. (it's likely using the fact many GMail users are receiving the same email to determine this is bulk e-mail and likely a promotion; there's not much you can do about it short of writing a manual email to every single user)