I would interpret this poll (related to this case) to show that of those who responded, the top bar represents those who would fit the "conservative" profile; the middle bar would be those who (in this case, at least) favor a more libertarian approach; while the bottom bar are those I would consider "progressives".
Of course, the case could be made to swap the top and bottom.
The main reason I consider the bottom bar to represent those of leftward inclinations is that they are the ones who advocate changing things such as drug "laws" to legalize marijuana use rather than simply recognizing that a bad "law" carries no authority.
On the other hand, "the right" also works to change gun "laws" that happen to bother them... so maybe there is (once again) no real difference between "left" and "right"; it's always about authoritarian or libertarian after all.