In the article, The Use and Abuse of Logarithmic Axes, Harvey J. Motulsky explained how bar graphs can be used for propaganda and misleading others. The article is at
He shows the following graph and explains, and quote
Since zero can’t be shown on a log axis, the choice of a starting place is arbitrary. Accordingly, the relative height of two bars is not directly related to their relative values. The graphs below show the same data as the graph above, but with three different choices for where the axis begins. This arbitrary choice influences the relative height of the two bars, amplified in the graph on the left and minimized in the graph on the right.
If the goal is to create propaganda, a bar graph using a logarithmic axis is a great tool, as it lets you either exaggerate differences between groups or minimize them. All you have to do is carefully choose the range of your axis. Don’t create bar graphs using a logarithmic axis if your goal is to honestly show the data.
So now you know. Never trust anyone that uses such tricks (politicians, pollsters, marketers, sales department staff, seos, and the likes). This one is also a great tool for fake news masters.