The text of article 5 doesn’t distinguish whether the attack on the NATO state was justified or even whether the NATO state attacked first.
This lack of blaming is partly why Turkey and Greece had to sign at exactly the same time, so that neither could take advantage of being able to attack the other whilst being themselves shielded by NATO.
“The Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all…” -
> The text of article 5 doesn’t distinguish whether the attack on the NATO state was justified or even whether the NATO state attacked first.
Arguably, the text of Article 5 doesn't have to, since an act of aggression breaches the obligations of Articles 1 and 2, as well as the pre-existing obligations which the Treaty explicitly does not alter under Article 7.
I see what you mean - although articles 1 & 2 seem to be treated more like guidelines rather than rules.
Otherwise I struggle to understand how any NATO member could’ve engaged in any of the overt or covert expressions of military force in Iraq 2003, Vietnam, Cuba, Iran, Guatemala, Chile, Egypt, or Algeria to name but a few.
In the given scenario above, Turkey attacks first, in which case Article 5 would not apply to a retaliation.