9.23 Api, even; ye, those who; anya-devata-bhaktah, being devoted to tother deities; and anvitah sraddhaya, endowed with faith; yajante, worship (them), te api, they also; O son of Kunti, yajanti, worship; mam, Me; eva, alone; (though) avidhi-purvakam, following the wrong method. Avidhi implies ignorance. So the idea is that they worship (Me) ignorantly.
 
'How it is that they worship (Me) ignorantly?' [i.e. the worshippers of other deities worship them knowingly, and hence, how can the estion of their ignorance arise?] This is being answered: Because-