We have to have names for things in order to communicate with each other about them. If we were to call what is now called Buddhism “realism,” as Nishijima Roshi suggested would one day happen, this could be confusing. These days the word “realism” generally seems to be synonymous with “materialism.” And Buddhism isn’t materialism.
We could just make up a new word. But that has drawbacks. It’s like the people who are concerned about the grammatical necessity of using gendered pronouns in English who propose to use new words like zhe, ze or zir instead of he or she. It’s awkward and nobody knows what the hell you’re talking about.
Maybe eventually we’ll get a word that works. But not yet. So we’re stuck with “Buddhism” for now.
Stuck. As in, immobile, solid, entrenched. You know what loosens such bonds? Water, that's right. Let the waves of enlightenment wash over you and dissolve the conceptual concrete in your mind.