Some can see the bigger picture and understand how classified information works. So you might say, "It's a bonkers conspiracy fantasy that Prince Philip had a mistress for years and they had a daughter together" and you can, because it is classified information (for 50? 70? years). People like yourself can describe people who espouse this as being stark raving mad, but do you know what...?
You can't get past what you've been told in the newspapers. As they are not allowed to mention it you can make a decision to hurl abuse at anyone who mentions it ...because, er, it's not official.