For me, bleeding heart libertarianism is not as much a philosophy as it is a marketing strategy. The origins of “liberaltarianism” are found in the fact that the conventional libertarian philosophy — embodied by property rights “absolutism” — simply does not resonate amongst the majority of people. It is difficult for someone to accept that, in the grand scheme of things, property rights are more important than, say, a welfare check that allows someone to survive.
Bleeding heart libertarianism is about re-packaging libertarian ideas in a way that is acceptable to others. It is not a call to abandon your ideals and principles. At most, it suggests that you ought to explore new angles of looking at what you already believe in. It is about accepting the fact that people do not agree with you and, as such, you need to change tactics.
People who reject the bleeding heart program out of a belief that it will dilute the message are simply unwilling to really come to terms with what the program is putting forth. Outright rejection of new ideas and perspectives is the same thing as a rejection of intellectual progress; it is a reactionary, conservative attitude that does not help libertarian philosophy.