The Book of Revelation, according to its opening verses, is a prophecy addressed to the Church.
Rev 1:3 KJV -  Blessed [is] he that readeth, and they that hear the words of this prophecy, and keep those things which are written therein: for the time [is] at hand.
If then as you suppose the antichrist cannot be revealed to the Church, whom is John the Revelator speaking to when he, being inspired by the Spirit, says this?
Rev 13:18 KJV -  Here is wisdom. Let him that hath understanding count the number of the beast: for it is the number of a MAN; and his number [is] Six hundred threescore [and] six.
If the number of the beast (a.k.a. the man, the antichrist) will not be reckoned by a wise Christian of the Church, to whom the letter of Revelation is addressed, then who is the wise NON-Christian with understanding and able to count the number of the beast?
Now I would agree with you that some of us may have Mr. Obama wrongly accused of being THEE antichrist (time will tell) but I am certain that he is an antichrist by his actions.
English - A=1, B=2, C=3, etc. ----BARACK = 36. 1+2+3+4+5+6+7+8+9------à +32+33+34+35+36 = 666
Greek alpha=6, beta=12---Χουσεΐν (Hussein) = 666
Greek alpha=6, beta=12--- Μπαράκ Ομπάμα (Barack Obama) = 738 = 6+66+666
Total Greek Gematria of Barack Hussein Obama = 1404 = the counted number of the beast
Now count the number of the Beast in Greek
English – A=6, B=12, etc.—President Barack Hussein Obama (second) = 1998 = 666+666+666
Hebrew BHO=666– see link http://www.fivedoves.com/ac/kevinh619-3.htm