Hinduism, which is not really a religion, but rather a collection of many syncretistic religions, and Buddhism can absorb other faiths without batting an eye. They are quite willing to add Christ, for instance, to their list of deities and religious teachers.
This is very similar to the ancient classical religions. They objected not to Christians claiming that Christ was divine, but rather to the claim he was the One True God, which of course meant their gods weren’t any such thing.
If one truly believes the Christian faith, you must believe what Christ said of himself, “No one comes to the Father except through me.”
This doesn’t mean Christians are required to be harsh or intolerant of others, much less persecute of those who believe differently. But it does mean that Christ made certain claims for himself, and to deny them is to deny Christ and therefore to cease being a Christian.
A perfectly logical definition of Christian, “One who claims to believe what Christ said about himself.”
“He that hath meditated Me alone,
In putting off his flesh, comes forth to Me,
Enters into My Being—doubt thou not!
But, if he meditated otherwise
At hour of death, in putting off the flesh,
He goes to what he looked for, Kunti’s Son!
Because the Soul is fashioned to its like.
...
Have Me, then, in thy heart always! and fight!
Thou too, when heart and mind are fixed on Me,
Shalt surely come to Me! All come who cleave
With never-wavering will of firmest faith,
Owning none other gods: all come to Me,
The Uttermost, Purusha, Holiest!
...
For who, none other Gods regarding, looks
Ever to Me, easily am I gained
...
I am alike for all! I know not hate,
I know not favor! What is made is Mine!
But them that worship Me with love, I love;
They are in Me, and I in them!
Nay, Prince!
If one of evil life turn in his thought
Straightly to Me, count him amidst the good;
He hath the highway chosen; he shall grow
Righteous ere long; he shall attain that peace
Which changes not. Thou Prince of India!
Be certain none can perish, trusting Me!
O Prithâ’s Son! whoso will turn to Me,
Though they be born from the very womb of Sin,
Woman or man; sprung of the Vaisya caste
Or lowly disregarded Sudra,—all
Plant foot upon the highest path; how then
The holy Brahmans and My Royal Saints?
Ah! ye who into this ill world are come—
Fleeting and false—set your faith fast on Me!
Fix heart and thought on Me! Adore Me! Bring
Offerings to Me! Make Me prostrations! Make
Me your supremest joy! and, undivided,
Unto My rest your spirits shall be guided.
...
Give Me thy heart! adore Me! serve Me! cling
In faith and love and reverence to Me!
So shalt thou come to Me! I promise true,
For thou art sweet to Me!
And let go those—
Rites and writ duties! Fly to Me alone!
Make Me thy single refuge! I will free
Thy soul from all its sins! Be of good cheer!
...
He only knoweth—only he is free of sin, and wise,
Who seeth Me, Lord of the Worlds, with faith-enlightened eyes,
Unborn, undying, unbegun.
...
Yet not by Vedas, nor from sacrifice,
Nor penance, nor gift-giving, nor with prayer
Shall any so behold, as thou hast seen!
Only by fullest service, perfect faith,
And uttermost surrender am I known
And seen, and entered into, Indian Prince!
Who doeth all for Me; who findeth Me
In all; adoreth always; loveth all
Which I have made, and Me, for Love’s sole end,
That man, Arjuna! unto Me doth wend.”
...
http://www.bartleby.com/45/4/12.html
These are not modern revisionism. These are excerpts from the Bhagavad-Gita.
My point? It is not a monopoly of any specific religion, to demand faith without compromise to one entity. The idea is as old as time. Many a "One True God" have been invented before.