I’m not condoning in any way the lack of attention by the controller...BUT...If in fact the aircraft was flying to low to be tracked by radar and flight rules were VFR, how could the controller have known there was any danger?
Don’t you know. The locals can do no wrong and the out of towners are always at fault.
And even if he did have them "painted" , how would he have communicated...were both those pilots monitoring a specific radio frequency under VFR? Is VFR flight following required in that area?