Read the passage carefully. He sits as God. He's opposed to God and exalts himself above God and everything that is worshiped.
[SUP]4 [/SUP]who opposes and exalts himself above all that is called God or that is worshiped, so that he sits as God in the temple of God, showing himself that he is God.
Again, from the interlinear:
2 Thes 2:4 ...he opposing and exalting himself over everything being called God, or object of worship, so as him in the temple of God as God to sit, showing himself that he is a God."
Titus did exactly that. He showed that he was a god. The text doesn't say how long he stays in the temple exalting himself, does it? Here's what Josephus said. What else are we missing?
AND now the Romans, upon the flight of the seditious into the city, and upon the burning of the holy house itself, and of all the buildings round about it, brought their ensigns to the temple and set them over against its eastern gate; and there did they offer sacrifices to them, and there did they make Titus imperator with the greatest acclamations of joy.