While I don't agree with any religion being taught to youth, Fundamental Christianity is the least appropriate. Progressive Christianity allows for some diversity in beliefs which, while limited, is still an improvement. It is also more in line with societal norms, which causes less tension and ill-will than the rigidity of traditional Christianity.
No, I do not think that progressive Christianity is necessary for today's youth, because the old values of Christianity are the right values. Progressive Christianity teaches that there is no right or wrong. That is not what Jesus taught. Jesus said that God is the same, yesterday, today, and forever. The message of Christianity does not need to change.
I believe that Progressive Christianity should be taught to only those who are actively seeking to learn more about it, I don't believe it should be a necessary requirement to be taught to today's youth. There are many different faiths and beliefs out there and everyone should be able to choose the one they wish to follow.
The question asks if children learning about progressive Christianity is necessary and when it's asked like that I have to say it isn't because children could easily benefit from learning about a different religion and it wouldn't matter. I believe Christianity is a good first religion to learn as it speaks to children quite well, but I don't think they should feel trapped in that religion as they get older.
While progressive Christianity is certainly more tolerant and open than conservative Christianity, it's still not necessary for today's youth. In fact, the majority of the people in the world are not Christians, and their children are not raised as Christians. The bulk of these children turn out just fine - meaning that Christianity (or religion in general) is not necessary.