Sometimes the referent cannot be physically observed, yet a demonstrative still appears. It can be rhetorically effective when context, description, or familiarity makes an otherwise intangible matter seem present before the mind.
«تعالت كي أشجى وما بك علة ... تريدين قتلي قد ظفرت بذلك»
You affect the air of suffering although no illness afflicts you; you seek to kill me, and in that you have succeeded.
«ذلك» points to the already expressed aim. Compared with a plain anaphoric pronoun, demonstrative wording can give the intended matter greater vividness and prominence.
The important question is how the expression presents the referent to the hearer, not merely which noun it could replace.