Dubium: Does your interpretation of Dignitatis Humanæ imply that the state cannot, even as the arm of the Church, limit the public profession of non Catholic religions if the professors are unbaptized (apart, of course, from the considerations of public order)? Put differently, has the church never allowed that exercise to the state?
Responsum: Affirmative. The state cannot, even as arm of the Church, limit the profession of false religions by the unbaptized, except insofar as they disturb public order.
For the most part the Church has been very careful of the distinction between the baptized and the un-baptized. Even anti-Catholic authors have remarked on this. For example, Thomas Hobbes:
From hence it is, that in all Dominions where the Popes Ecclesiasticall power is entirely received, Jewes, Turkes, and Gentiles, are in the Roman Church tolerated in their Religion, as farre forth, as in the exercise and profession thereof they offend not against the civill power: whereas in a Christian, though a stranger, not to be of the Roman religion, is Capitall; because the Pope pretendeth that all Christians are his Subjects. For otherwise it were as much against the law of Nations to persecute a Christian stranger, for professing the Religion of his owne country, as an Infidell… (Leviathan, ch. 44, Of Spirituall Darknesse from Misinterpretation of Scripture; cf. Thomas Pink, “Suarez and Bellarmine on the Church as Coercive Lawgiver,” p. 188).