Indeed. Its a problem of language evolution.

To summarise a few centuries of Philosophy very briefly: A lng tie ago there were Rationalists who thought everything could be proven by pure reason, and Empiricists who depended on observation of the external world. Because Reason was often used in contrast to emotion (and because of the association with logic and mathematics) "Rational" evolved into a general word for reasonable or well argued. The modern rationalist movement is about thinking clearly and coming to correct conclusions, which can't really be done by relying exclusively on pure reason. (Hence why moral rationalists in the original sense don't really exist anymore)