I don't see any way of getting around this that isn't just rife for abuse. I guess/hope that Gmail learns from user behavior, so if enough of them start moving the mail to the Forums list (which is what I think it should be, Social Updates implies some personal update from Facebook/Twitter/G+, not newsletters), it would automatically filter there instead.

EDIT: Also, many users might feel like Promos is the right tab. For example, Weight Watchers emails me recipes, which is a bit like a developer getting Javascript tips. This also goes in Promos, and that seems like the right place for it, even though it's useful/actionable information.