The word "deny" in the Epistles of John means to "disown".
tr.v. dis·owned, dis·own·ing, dis·owns
To refuse to acknowledge or accept as one's own; repudiate.
According to the word "deny" as it is used in the KJV, there is something terribly amiss with your understanding of how the RCC is of that spirit of antichrist.
Are you able to prove that the RCC "disowns"/"deni es" Jesus Christ?
Everything they believe and do, disown Christ. E.g., they worship Mary.
One should rather point out something do or teach or believe that does not deny Christ.
The sheer number of Roman Catholics belies and disowns "Christ's Own" who are, and must and will be, "FEW".