That's not a cop out line. For some websites, yes, it very well could be, but there is a legitimate purpose to it as well. Anybody can go on a website and enter "maddox@xmission.com" in the email input box for a subscription to SpamMePlease.com, even people who aren't Maddox. Putting that line in the email is a way of saying "you might not have done this, so here's a quick link you can use to tell us to fuck off."
You can argue that they should use a "confirm this subscription" email instead, but the two options aren't that dissimilar when you think about it.