I'm still uncomfortable with folk's use of the word "hinayana." Many Theravadans (and non-Theravadans) consider this word a perjorative, as expressing the dismissal of Theravada as a "lesser vehicle." What I understand from the historical scholarship is that the sects that were truly considered to be "hinayana" faded away over time (BCE into the CE). Theravada was not considered to be part of the "hinayana"
I have practiced with both traditions, in my case Thai Theravada and Soto Zen. For me, the suttas and the sutras need to be careflly evaluated as to the their historicity and authenticity. If a sutta or sutra is found not to be not likely Buddhavacana, then I feel we need to accept the sutta or sutra on its own terms and appreciate its meaning and beauty as it is. I think it's fairly clear that there's a lot of Buddhavacana crossover in the Pali Canon and the Chinese Canon, and there's clearly some post=Buddha fictional accounts in both the Tipitaka and the Tripitaka (Abhidhamma, for example).
If you put an arrow to my head and forced me to choose between Theravada practice and Zen, I couldn't choose. I'd let the arrow fly, and then start to ask questions about what kind of arrow, who is the archer....
I've listened to debates about the expansiveness of American Zen, the "selfishness" of Theravada and the arahant ideal, the deity fictions in some Mahayana. I just wish that sincere practitioners would see the beauty in each of these practices and focus less on the differences. The best scholars seem to feel that there's far more connecting Zen and Theravada than what separates the two. I personally know some Thai Bhikkhus who are amazing Bodhisattvas, and some Soto Zen teachers who are excellent teachers of meditation and the development of the Way, who would function quite well in a Thai Forest environment.
Hinayana doesn't really exist. Who is to say that "hinayana" shouldn't be used? However regardless whenever someone uses the term hinayana, they're just using a useless word. It's at their own expense, not that of others. In my thought, I have always wished that the terms Theravada and Mahayana didn't exist. There really isn't a difference between the two. Scriptures are scriptures. The Buddha's teaching was the Buddha's teaching. And each person has their own analytical reasoning they should rely on. There is no "vehicle" but the one right inside our own self. There's no need to hide behind the word Mahayanist, or reserve yourself to "the Theravada." There is nothing selfish about nibbana. Only through selflessness can one let go of ignorance and attain nibbana. In reality, bodhicitta can be cultivated by any follower of dharma. Nibbana is and has always been the essential goal of Dharma, it's what the Buddha sought for, found, and based his teaching upon from the start. A person who attains nibbana has achieved that goal and is a noble one.
I think it's important to keep in mind, that every Mahayanist in the world is not really on their way to becoming a sammasumbuddha. This is an unrealistic notion. Some of them are, perhaps. And some of them will perhaps start on that path in the future. But there is no need to be so rigorously exclusive.
To label someone or an entire tradition "selfish-oriented" because they are trying to find release from samsara, is wrong, counterproductive, and such a person clearly does not
have bodhicitta. A bodhisattva in that sense, would rejoice and delight and support any being following their path to nibbana.
Being dogmatic, is being dogmatic. Even if you're using the mystical veil of emptiness to disguise it. Beings are reborn because they are ignorant. Beings are released from rebirth by destroying ignorance, achieving the first nibbana element. Even the Buddha himself, upon dying after achieving nibbana, was released into parinibbana (the element without remainder).