the filling in of the roman sewers, destroying the baths, and losing the recipe for soap for a thousand years all started and ended well before the pilgrims.
US christianity is not the beginning of that faith.
BTW- he was in fact being quite completely literal when he said, that: not metaphorical in any way. For many years, people who purposefully injured themselves were considered better people for it, and bathing was something that only pagans did, for which they burned.