The reaction (image below) can be abbreviated as HCl → H+ + Cl-. How is this apparently important omission justified? A)

It isn't justified, and the abbreviation is an error.

B)

It's understood that H+ doesn't exist on its own in water, and image are both aqueous.

C)

It's generally understood that H3O+ is a hypothetical intermediary.

D)

Because water isn't important to the reaction