A demonstrative can be chosen to praise a person by placing that individual prominently before the audience's attention. Singling someone out before describing a virtue may intensify the effect of the praise.
هٰذَا أَبُو الصَّقْرِ
This is Abū al-Ṣaqr.
In the source's poetic discussion, the individual's presentation supports praise; the accusative «فَرْدًا» is also explained in connection with commendation. This does not make «هٰذَا» a lexical synonym for “excellent.” Rather, demonstration combined with a praising context yields that force.
The same form can occur in a rebuke. Its basic referential function and its contextual rhetorical purpose must be kept distinct.