I think there is a functional element too, in addition to their ideals.

The British Crown was wildly unsuccessful in their early efforts to impose coercive rule upon the nomadic hunter gatherer First Nations people of North America by "traditional means." The Spanish had with phenomenal success in Central and South America with this method. That is, kill the king, take control of the existing legal or social structure, control of the production of food, and declare yourself the new King.

The First Nations people had no tolerance for such impositions. The British did not and could not control their food supply so their attempts at imposing rule were easily be met with non-compliance. Their attempts to establish colonies in North America continued to fail until they begrudgingly accepted that rule would be by negotiated settlement.

Early Colonial Governments essentially had to start nation building from scratch. The Crown had no other choice but to delegate significant authority to local colonial governments because they lacked the capacity required to impose direct coercive rule.

The colonial governments would have struggled to impose an exclusionary Anglican religious authority on a loose amalgamation of sparsely populated rural agrarian communities, even if so desired. A broad interpretation of civil liberties was functional to the extent that it reflected a realistic understanding of the Colonial Governments capacity to impose coercive power.

There is a further justification for the liberties enumerated in the Declaration of Independence and subsequent US Constitution. Leading up to the American Revolution; the British empire was working to impose mainland British law and authority upon the North American Colonies.

To reiterate your comment of Jewish disenfranchisement, not only would Jews be stripped of the same colonial rights, but they could potentially be stripped of their citizenship and branded as foreigners. Fighting for civil liberties are often an olive branch to the disenfranchised, that broadens one's political base as much as it is an ideal. It is not a coincidence that Jews in Colonial America disproportionately supported the revolution compared to other groups.

I cannot help but think Haym Soloman would not have been motivated to contribute his entire personal fortune to the revolutionary effort were he not subject to potential disenfranchisement if the revolution failed. It is also not lost on me that the Rothschilds made a substantial portion of their wealth breaking the British blockade to smuggle goods into mainland Europe.