Bubble charts show the value in the area of the circle, not its diameter. The chart is accurate but we're accustomed to seeing inaccurate charts using diameters, usually to sensationalize an article.
Surprises me - pie charts are properly used only to display proportions, and in a pie chart the area is proportional to the angle is proportional to the length of the arc, so there should be much less scope for confusion? We should all have good intuitions for our share of the pie or pizza, no...? :-)