All evidence to the contrary on humility, but you have yet to explain how your objective truth is quite opposite from what I've stated.
The sharing of creeds, the shared core beliefs the shared similarities in liturgy and doctrine to varying degrees, the acceptance of certain sacraments and rituals between the various denominations.
I think the issue you seem to have is one both Reaganaut and I have pointed out, you are getting caught up in lumping everything even remotely labeled “Christian”, everyone and everything that simply invokes the name of Christ into one big pile. There are and have been many sects come and go that say they are Christian, but like the extreme example I gave you earlier of giving a Muslim a pass because they say they are “Christian”, saying it and being one in realty are two different things. The words are not enough, whether they be on the lips or on the building.
The core “denominations”, the Catholics, the Orthodox, and the main line Protestants share far more in common than they have disagreed on, something that becomes more and more a part of the Christian world every day. Indeed the many historic disagreements that over the centuries under wrongheaded guidance and leadership inspired by the Evil One, would have set us at each others throats are fading to some extent, at least in importance, as we all stress the commonalities that we share.
Are there exceptions, certainly, but oddly enough the exceptions have been always in the hands of the few (and growing fewer) But I am blessed to live in a time were I see Fire and Brimstone Southern Baptist cry with their Catholic friends when their beloved Pope passes, where I have seen a hundred Methodists, Catholics, Episcopalians, Lutherans, Baptists and others, both lay and clergy, stand in a circle together holding hands while an Anglican Priest from African with one of the most beautiful and distinctive voices I have ever heard offers an almost poetic prayer to end a weekend of sharing Christ's message of Grace and Salvation with 42 prisoners, to follow a historic tradition where whether I am standing in an Orthodox sanctuary or a Methodist prayer meeting I feel at home surrounded by fellow followers of Christ.