When to apply

My passport has an official expiry date in December. But many countries (maybe most or all - certainly all the ones I travel to) require a passport to be valid for at least 6 months after you enter. So in practical terms, my passport has already expired. But when I go to the online website to renew my passport, it asks me to: "Please consider coming back at a later date to apply. This will help us support those with urgent applications, who need our help the most." What is this nonsense? Doesn't the passport office know that a passport stops being usable 6 months before the official expiry date? Misinformation like this could seriously impact someone who has a passport, but doesn't travel much and doesn't realise that a passport with less than 6 months remaining on it is almost useless.