I am sorry, but the letter about our abandonment of Christian ideology being responsible for all our current problems is just nonsense.
The social changes mentioned, from abortion rights to marriage equality, are vast social movements We the People insisted upon, no longer held back by the dead hand of ancient dogma.
The Christian values not mentioned in the earlier letter would include genocide, slavery, the subjugation of women and girls, extreme homophobia, and currently trying to use the government, in dreadful violation of church/state separation, to inflict 8,000-year-old Iron Age mythology on today’s science classes.
It is the freedom from the dead hand of religious dogma that has allowed almost all social progress. After all, the Puritans were the equivalent of the American Taliban: a priggish, intolerant society that, after they executed over 20 (mostly women) for being witches, thought the Native Americans were savages.