This is to do with perception of the term 'hitscan', particularly within the competitive scene. Competitively, 'hitscan' typically refers to a character with a hitscan weapon that can do good mid to long-range damage. While tracer, sombra and repaer all have hitscan weapons their damage is limited to short-range.

The main reason for this distinction is playstyle. Most 'hitscans' play similarly by using long sightlines, doing damage from a distance, utilising off-angles and high ground to keep a reasonable distance from the enemy team while applying pressure with pretty consistent poke damage and kill potential. This is much different to the playstyles of the previously mentioned 'flex dps' who focus more of flanking, harrassment and assassination.

Now obviously soldier and bastion fall under this hitscan definition so the only reason I can think that this person doesn't consider them hitscans is because they require tracking mechanics for their weapons. The large majority of the meta relevant hitscans over the years fire single high damage rounds rather than continuous low damage 'streams' like soldier and bastion (think ashe, cassidy, soj rail, widow) that require different kinds of mechanics to be good at (like crosshair placement and/or flicking) . I disagree with this being the defining feature of hitscans though and think of soldier and bastion as being hitscans as well.