That's the whole point, Ken. The F3 was never slated as a fighter, it was an interceptor. The difference being modern usage of the term "fighter" rather than the traditional means a distinction between an aircraft that does ground attack from one that does air to air. That said, we never referred to the F-3 as a fighter. But the key to air superiority is in its definition.
A dominance in the air power of one side's air forces over the other side's during a military campaign. It is defined in the NATO Glossary as "That degree of dominance in the air battle of one force over another that permits the conduct of operations by the former and its related land, sea, and air forces at a given time and place without prohibitive interference by the opposing force."
You don't have to be a fighter to achieve air superiority. We referred to our job in the F-3 as air defence.
The modern term "air superiority fighter" was coined as a means of describing the claimed effectiveness of an aircraft in achieving that state. When that wasn't enough to make your jet stand out from the crowd, even better terms were invented - "air supremacy" and "air dominance". All of which actually mean the same thing in military terms.
The A-4 was used as an air defence aircraft, but it wasn't really what it was designed for and it didn't have the kit or the punch to do it. Strangely the RAN used the G model for their air defence of the fleet armed with a couple of early AIM9s. I'm sure they thought it was the way forward.