Religious liberty has been championed by Baptists of all soteriologies.
Thomas Helwys, a General Baptist, espoused it at the very beginning of recorded English Baptist history.
"For we do freely profess that our lord the king has no more power over their consciences than over ours, and that is none at all. For our lord the king is but an earthly king, and he has no authority as a king but in earthly causes. And if the king’s people be obedient and true subjects, obeying all human laws made by the king, our lord the king can require no more. For men’s religion to God is between God and themselves. The king shall not answer for it. Neither may the king be judge between God and man. Let them be heretics, Turks, Jews, or whatsoever, it appertains not to the earthly power to punish them in the least measure. This is made evident to our lord the king by the scriptures."
— A Short Declaration of The Mystery of Iniquity, 1612
John Leland, a Calvinist, championed freedom of religion and had a hand in convincing Madison that the First Amendment was necessary to prevent establishment of state religion.
"Yes, from the beginning of Christianity, down to the close of the eighteenth century,
A.D. it never prevailed among a people, of any considerable consequence, but they would either punish or pamper it almost to death: either to proscribe it, or make it a principle of state policy. To say that the government of the United States is perfect would be arrogant; but I have no hesitancy in saying, that the
Constitution has left religion infallibly where it should be left in all government, viz: in the hands of its author, as a matter between God and individuals; leaving an open door for Pagans, Turks, Jews, or Christians, to fill any office in the government, without any religious test, to make them hypocrites: securing to every man his right of argument and free debate: not considering religious opinions objects of civil government, or any ways under its control: duly appreciating that Christianity is not a scheme of coercion; but only calls for a patient hearing, a dispassionate examination and a rational faith."
You want proof texts; Baptists have drawn the inference from their understanding of God and man and the witness of the New Testament. We will, one day, give account to God for ourselves. The state will not stand before judgment, but individuals, and the state has no right to interpose itself between God and man in such a serious matter.
I have to ask why someone who calls himself a Baptist would think that enforced religion is a virtue. The colonial American Baptists were exiled, whipped and thrown into prison because they ran afoul of the Congregationalist and Anglicans.