...and there's more on CS definition

My view is that the definition of CS is still somewhat in flux. If it was de facto, surely someone would have gotten round to editing the Wikipedia entry by now, which reads: “Content strategy refers to the planning, development, and management of content—written or in other media.” Perhaps it’s Kristina’s definition that should come out on top. If so, someone ought to change the world’s most referred-to crowd-sourced reference manual.
I do agree with the premise of your argument regarding ads, but in the interests of balance, ads are easy to find and the type of “ad” Professor Lavine has been guiding us to is the more subtle emotional variety per the “Your Verse” iPad “Ad”. The feeling engendered by the experience of the “Your Verse” ad is something that I have felt is important to appreciate and understand the power of, as it applies to audience engagement.
Rather than Strategy per se being the focus of this course, I think it is really “Audience Engagement”. The wording of the title could be adjusted to reflect that, but that really couldn’t be determined beforehand. Feedback from practicing experts like yourself has highlighted it as something that could be revisited.