User blog comment:Rappy 4187/Technical Update: July 27, 2016/@comment-5645428-20160731221156/@comment-126761-20160801150731

Generally, Insights lists concentrate on content namespaces rather than the rest of the community. For example, we want to avoid Message Walls and Forum posts appearing on popular pages as those are fairly niche interest most of the time.

That said, a namespace selector is an interesting idea - and I can understand how it can be helpful to see pageviews info for other sections of a community. I'll bring it up with the team.