“A libertarian is a liberal who hates paying taxes.”
Its not true all the time but its true most of the time. Write out the liberal positions and libertarian positions and you will see there is great similarity.
Some libertarians are very far from being liberal but many are very close to it
I’ll give you some of the time but not most. Libertarianism is too much about limited government to be fundamentally compatible with liberalism. Even when they share a position on an issue, they’ve usually arrived at it through different reasoning. The basic substance is different. The Koch brothers are libertarians and liberals rightfully recognize them as an arch enemy. Confusing libertarians and liberals is sort of like confusing Sikhs and Muslims.