Libertarians and Republicans are not the same thing, just as anarchists and Democrats are not the same thing. Many people have complex views that don’t fit neatly in boxes. Libertarians and Republicans often share goals that is enough.
Libertarians are “strict constructionists” of the Constitution. That is why they have many things in common with conservatives - other than “cultural conservatives” who want to impose their idea of religious morality as an official government standard.
Libertarians are for protection of individual rights against the majority.