Either:
1) You don't know what libertarianism is
2) You don't read the economist very closely
3) You meant liberalism
Given you think that the economist dogmatically believes in less tax, regulation and trade barriers, it seems more likely you don't actually read the newspaper very closely.
Take healthcare in US for instance. The economist consistently favours more government intervention and higher taxation with a single payer health system. Just taking one example from the current Europe editor (I think): http://www.economist.com/blogs/democracyinamerica/2013/09/he...
> In fact, government intervention is often necessary in order to bring comprehensibility to a bewildering private landscape.