Why are people labelled "false prophets"?

I realize the little minds that make fun of Christ will find this hard to believe but the only Prophesy of Christ that is left to come true and it really is not one is his promise of his return. The Temple was destroyed in AD 70 exactly as he said it would not one stone left up on another.His Crucifixion and Resurrection how St.'Peter would end his last day's and one every one can see for them selves and that is his Church would endure until his return and claim it as his bride and the gates of hell will not prevail against her and after 2,000 years and many bad popes and priest and members and a protestant revolt plus for almost a thousand years the Arian heresy and all the constant attacks against her teachings she the Holy Catholic Church is still here as proof.