And then, after WW2, the bishops of the world gathered and ignored all that? Is that the Church you want us to believe in?
At Vatican II they looked at what happened and tried to address those issues. Why was there no hope? Why were there such divisions between catholics and protestants, between catholics and jews, between catholics and atheists? Did those play a role in the wars that enveloped the world? 
To preach the Gospel, they tried to recover a sense of Jesus as the creator of peace. They promoted the community aspect of the liturgy. They reassessed our ties to the Jews, and to all people, emphasizing what we share. They reaffirmed conscience as the place where we meet God against the totalitarian authoritarianism.
Reemphasizing these things may have caused some defections from the Church, but those defections were coming anyway as people discovered "I did what I was told to do" was not a defense. The pre-Concilliar Church needed to change so that Christ would be more visible.