OK. I was confused because I had interpreted the word “primary” as “most important”. But it was actually meant by “most basic” or “not coming from or dependent on something else”. So now I got it. Lobha, dosa, moha, alobha, adosa, and amoha do not belong to dhatu. Instead, six dhatu come from the six hetu.
But here is another question.
Those six hetu causes everything in 31 realms. i.e. Paramatta Dhamma(except nibbana) are caused by six hetu.
But lobha, dosa, moha, alobha, adosa (except amoha) is also cetasika.
So I guess there are some contextual differences between the lobha, dosa, moha, alobha, adosa as a cetasika and the lobha, dosa, moha, alobha, adosa, and amoha as a six hetu.
Let me know what it is.