[infollafago]

Buddhists do use the term adhamma, though. So perhaps the issue/question has to do with how we define dhamma/dharma.

Just the suttas, and if so, only the Pali version of same?
Among the suttas, do we include all the suttas?
Abhidhamma -- yes/no?
Prajnaparamita?
Mahayana in general?
Pure Land sutras?
The Zen canon?
Nichiren?
Tantra?
Vajrayana terma?

And besides the answers we may come up with invidually, we may also have to delineate our relationship to Buddhist institutions and communities. "Sangha" is one of the Triple Jewels after all.