It must be the same tendency that causes a five-year-old to poke a stick into a red ant mound.
Of course libertarianism is the same a liberalism, read Hayek if you don't believe it. However, simply because American socialists expropriated the word doesn't change its meaning. A liberal society is one that believes in competition as the best economic system and believes that the governed must give their consent for the state to use its coercive powers in all cases. Classical liberals also believe that laissez-faire utopianism is the road to anarchy. They believe a moral society is the only way to keep the tyranny of government at bay.
Once again invoking Hayek, conservatives seek to maintain the status quo. The current status quo is rampant socialism tending toward national socialism and has resulted in the rise of the so-called "neo-cons." To call one's self a conservative today means that one supports socialized medicine, welfare state rights for illegal immigrants, soviet-style international adventurism, and runaway deficit spending by an ever more fascist government. Given that, I'll take the liberal label any day.