I'm split on how to interpret this card. On the one hand, by regular logic, if you coose a unit to be affected by an effect, then you are targeting that unit with that effect. On other hand, the card says "destroy a unit" and not "destroy target unit". So the question becomes, did the designers purposfully not write "target" for it to avoid "cannot target" effects, or is it an oversight?
Does anyone have an idea?
In your example the card resembles much more likely the aimed gun than the shootgun (since the card always hit what you coose to hit). Using out of game logic, if you fire a gun with the intention of hitting that specific thing you are targeting it, no matter how inaccurate the gun or how lazyly you aim (if at all). For you not to target you wuld have to shoot the gun fore some other reason.