Even today, protestants have been accepting of same sex marriages, female clergy, birth control, and even abortions than the monolithic Catholic church, and that's not about to change anytime soon.
That's only superficial, as protestant countries (and especially calvinist ones) transcribed into everyday non-religious morals all kinds of religious tenets, from the "protestant work ethic" to modern versions of puritanism like "political correctness".
Based on these replies, I'm wondering if there wasn't pop-history hit-piece on Protestantism that I'm not aware of.
Just for for the record, I'm an atheist myself.
Some did yes. For others the appeal of Protestantism was flexibility.
Same sex marriage, ordination of female clergy and birth control are not christian doctrines 'progressive' as they may be.
Which is why modern protestant denominations in the US for example are even more Old Testament and wacko than catholics.
And of course the same strictness has been inherited by atheists that grew in a protestant culture, contrary to classical humanism.