First of all it is not irrelevant. You were still refused and on the application you are asked whether you were refused. So did you choose not the write it there or was it a mistake? Sounding more and more like a choice. You can do nothing about it now.That’s terrible !!! I though it was irrelevant because they (US embassy) finally granted me the visa and I have traveled to US without a problem. So you think that with a refusal like this, even though they invite you to reapply, it will be a worthless effort to apply again?