I agree with you.
According to the Concise Pali-English Dictionary (CPED) used in Digital Pali Reader (DPR):
akusala: demerit; sin; bad action. (adj.), unskilful. (nt.)
Perhaps, in a neutral sense (not taking side on either 'good' or 'bad') 'unacceptable' might be used for 'akusala' (อกุศล).
I learned that an old Persian religion worshiping the God of Land (Asura อสูระ) somehow came into conflicts with a newer (Hindi) religion worshiping the God of Wars (Rama ราม). The old religion lost that war (farmers vs warriors) and we now say Asura is bad or unskilful.
Note. The original book Buddha Vacana was compiled by Venerable S. Dhammika and was published by the Buddha Dhamma Mandala Society.
The digitisation work was done by group leaders of the Camp Nirvana Singapore (CNS1996) organised by Nanyang Technological University Buddhist Society (NTUBS)