I believe that inconsistency is factored into, and indicated by the error bars and the width of the range indicators for each graph.

I'm not sure that "we might not be measuring the right thing in the first place" is the kind of error that can be sufficiently accounted for by error bars.

Since it's not from subject matter experts, expect things like sampling bias and administrative reporting issues to be completely neglected. That is to say, the uncertainty estimate is simply based on observed variance.