The term lemmings may be based on myth but the "TERM" lemming as referred to political behavior has been in use for hundreds of years (I'm sure that someone will attempt to correct me on my "liberal" use of the time period). So, the term is not necessarily incorrect as used, even if some liberal wishes to find exception with it's use regarding their group behavior. Perhaps their liberal practice of following, is also in line with the old Pied Piper tale since they follow a leader that is playing music and they are following him to their demise.

In case you fail to see the humor of liberals being called lemmings, it could very well be that the term is used as a physical and characteristic of their species.

Taken from Wikipedia:

"A lemming is a small rodent,.."
"Lemmings are subniveal animals, and together with voles and muskrats,......also includes rats, mice, hamsters, and gerbils." [a very good resemblance to liberals]
"The behavior of lemmings is much the same as that of many other rodents which have periodic population booms and then disperse in all directions, seeking the food and shelter their natural habitats[earners in liberal's case] cannot provide." I think they described liberals very well.