From Pepys's description of the Puritans I can't say much for their view of Christianity, and Cromwell was by no means the worst of them. (Pepys, incidently, had some admiration for Cromwell's political and military prowess.)

You may be right about the sex part, but I doubt if it was due to any love of pleasure. I suspect it had more to do with the Biblical command to go forth and multiply. There was only one way to do that back then, and if a man was not doing his duty in that regard he was disobeying God. I think some sects of Puritans (for they weren't all of one mind) also permitted betrothed couples to sleep together.

As to Christmas, by statute and international treaty it should be confined to December 23 to January 1, and I am being generous there. Let people get around it by singing advent carols.

Thanksgiving doesn't seem to have so long a lead-in time as Halloween and Christmas, which is something the turkey and pumpkin producers should be working on. . .