Admit it. Love it. Sing it. It's true. Development of Doctrine is the appeal. There is a very Christian, even biblical, basis for the Development of Doctrine. That's what made it so easy to exploit by various mainline Protestant denominations.
Want to change teaching? Want to call good what was once called evil? Want to call evil what was once called good? No problem. Development of Doctrine! Oddly, when it came to homosexuality, DoD was both appealed to and denied. On one hand, you'd think that Protestants accepting homosexuality never heard of the concept. If you condemn homosexuality, then you can't eat pork or you must stone adulterers to death! Because, apparently, there was never such thing as the Development of Doctrine. Apparently the Jerusalem Council never happened.
And yet, they would also appeal to the same concept if pushed back by the clear and obvious fact that even in the New Testament, homosexuality is considered the epitome of sexual sin. Maybe, they would say, but that's back then. Now we're discovering new revelations every day, and it turns out homosexuality is just fine. It's Development of Doctrine!
That's how they do it in downtown mainline Protestantism. For the Death Penalty, Pope Francis has taken a page from the old Mainline Protestant playbook. That appears to be a growing trend with the Catholic Church I've noticed. He has insisted that we don't need the death penalty since prisons will do the job. I'm not sure where that's true. We still have violence in and out of our prisons, and we've seen multiple cases where violent criminals have escaped. And that's here. There are other countries where it seems hell and gone from the reality that their prison systems are keeping them safe.
But he says so, and has therefore changed what the Church taught for most of its existence. He has redefined its teaching to say that what the Church officially taught was acceptable is no longer acceptable. We won't get into the rather shaky premise of our prisons' ability to keep the peanut gallery safe. We certainly won't compare this to his other statements about abolishing life in prison sentences.
It's enough that he said the Church must change its teaching. One thing we learned from Protestants over the years is that once you begin changing your traditions, it's a bit like eating potatoe chips. Once you start, you just can't stop. If what was once good - and right - is now evil when we all know things really haven't improved that much in our world, it's nothing to say that what was once wrong can now be right. It might take a few, but you'll get there.