Ok one must actually read the passage to understand what is being said.
The disciples ask two questions, Jesus gives two answers. What will be the sign of the end of the age? And when will he return? All those horrific things that Jesus said we're the signs of the end of the age, and they will happen before that generation passed away, and it did the passing of that age ended with the final destruction of the temple in 70 ad.
But as for the coming of the son of man, there is no sign.
The disciples ask two questions, Jesus gives two answers. What will be the sign of the end of the age? And when will he return? All those horrific things that Jesus said we're the signs of the end of the age, and they will happen before that generation passed away, and it did the passing of that age ended with the final destruction of the temple in 70 ad.
But as for the coming of the son of man, there is no sign.
Think about it