Should food grown with natural fertilizer say "Created with feces!" On the package?
Similarly, someone might not know what canola is - they may know it by the name rape. And some people avoid it - maybe the package should say "Warning! Rape oil."
Certainly that's additional truthful information, but it's also more misleading, not less.
Sinilarly, because the average person (maybe including yourself, judging by your complaint) does not know how nuclear physics works, a clearer statement on packaging would actually cause more people to believe incorrect things.
So what should the logo be? The radioactive trefoil symbol? You'd think that's the most "honest", but that's not an accurate depiction either, because irradiating the food doesn't cause the food itself to become radioactive.
This is why I hate big-food. They use any and all opportunities to mislead about what truly is going on.