Fredo wanted to be in his father's business to begin with so it was not Vito who forced him into the criminal activity.

And Vito was not a liberal/modern loving father. I think Vito had some basic values, such as responsibility for the family (and friends) comes before individual freedom, self expression, or even before protecting the nation (in case of Michael). He was deeply disappointed when his children went to war for other people, let women /or the appetite for women guide them, let their anger guide them over protecting family and the family image. I think he thought that this was the way to happiness.
At this point however Fredo was clearly ruining the family image in Vegas, with the sexual stuff and getting slapped etc.