Technically it is related to the content and usability of the page as a whole. It falls under the umbrella of feedback on the user's experience with the site.

I think it's myopic to dictate what is and isn't up for discussion, to say "well that's not the point, just ignore it." If the ad is so distracting and off-putting that the user doesn't even get to the content, that is pretty important.

And if that post rises to the top, the message is that a substantial amount of people are having a similar experience.