They follow European conventions, where "liberal" follows from the original "liberalism", i.e. the XIX century movement asking for trade liberalization (in a context of widespread protectionism by absolutist nation-states), a pro-business but socially conservative aggregation. Most "liberal" parties in Europe are right-wing in a similar way.

It's only in the US that "liberal" came to mean "socially progressive" for some reason, and only relatively recently (i.e. at least post-LBJ, I would say, if not later).