It would be helpful to read the history of Freemasonry and Anderson's Constitutions of 1723.
The Old Charges - combined Charter, Book of Constitution and Ritual - show that the Operative and early Speculative Masons were necessarily Trinitarion Christians. The Operative Lodges had, especially in mediaeval times, been intimately associated with the Church due to the employment of Masons on cathedral and church building work.
For example, the Cooke MS (c1420) says (as translated into modern English) "it behoves first principally to love God and Holy Church and All Hallows". All Hallows refers to the Saints. The real change came in 1723 in the First Charge of Dr Anderson's Constitutions 'Concerning God and Religion' which states "Tis now thought more expedient only to oblige them (Masons) to that religion in which all men agree, leaving their particular opinions to themselves". The wording was changed in 1815 to read "Let a man's religion or mode of worship be what it may, he is not excluded from the Order provided he believe in the Glorious Architect of Heaven and Earth and practice the sacred duties of morality".
This Charge had the effect of "dechristianising" the Craft, thereby enabling Jews, Moslems, Hindus, Buddhists etc. to become members.
The Charge After Initiation states that the discussion on all topics of a political or religious nature is forbidden in the Lodge.
The general effect of the changes made is to abolish the introduction of [b]sectarian[b] religion into our Lodges and to enable men of all religions to meet on the common ground of a belief in a Supreme Being - the G.A.O.T.U.