You take three samples and two of three get shown the same thing. What happens here is both A groups will show different results until your sample grows enough that the CI window becomes small.

This helps to show the effect of a low sample from a non-uniform distribution.

A lot of people (me included) think they know statistics, but they don't.

The blogpost in OP also tries to explain the same thing - you shouldn't do statistics without understanding what it is your doing.