Why do some Christians believe the second coming of Jesus already occurred, when Daniel said knowledge must increase first?

Jesus tied some of the end time events to what Daniel prophesied. One of them is the abomination that causes desolation and the other one is what an angel told Daniel directly, that **knowledge shall incRease** (a prophecy that has been fulfilled in recent times) and **many shall move to and fro** (transport using airplanes from one corner of the globe to the other). Since these two have been fulfilled then the abomination that is yet to cause desolation is yet to appear but some Christians seem to believe that Jesus already appeared to the 1st century AD church, why? >"So when you see standing in the holy place the abomination that causes desolation..." (Mathew 24:15) The event above has not yet happened but the other two prophecies of Daniel happened.