Unfortunately, some people more enthusiastic within this new approach started to denigrate everything that have preceded them as being inferior while, at the same time self-applauding themselves. Theravada was already established in Sri Lanka, while only in mainlaind India, schools like the Sarvastivada were the target of Mahayana attacks. Therefore to call Theravada as Hinayana is not only depreciative, but also historical ignorant. You can't compare them. One can attend UCLA and be communist and another can attend New York University and be fascist.
School are something different than philosophical affiliation.
Zen, Gelug, Nyingma, Pure Land are schools, and within them we can find many hinayanists, mahayanically speaking. The spiritual ideal of Hinayana is to reach liberation for oneself. It is exemplified in the Arahat figure, that attains the tranquility of nirvana and does not come anymore to the realm of birth and death, however it is not the complete Buddhahood but rather a state of saintity. Well, this is somehow funny to hear. In reality, there is a large quantity of words whose original meaning were changed by the Mahayana schools.