I believe that the overriding reason for the failure to teach authentic Catholic beliefs and to enforce the teaching thereof is: cowardice. God and God thru Christ will us to lead lives of purity and sinlessness. When it comes to those areas where our strong (and sometimes difficult to control) desires conflict with the demand for holiness on our part, our priests, from the Pope on down, and who would live 'in persona Christi,' fear to face those great multitudes who wish to give precedence to their desires. When it comes to fornicaton, homosexual acts, abortion for convenience' sake, giving up or scaling back confession, and other hard doctrines, our Church has in many cases abdicated. For many priests, the cowardice manifests itself in the desire to be popular. And the same manifests itself at the top as well - when high prelates consider the numbers of supposed Catholics who might pull out if they were actually confronted with their sins, as well as the nature of sin itself (so conveniently swept under the rug these days). Our Church has shown itself to be chock full of raging cowards. And they have brought pain, shame, and horrific suffering to many. It's hardly surprising, given that any pulling away from God and holiness (though we are all tempted to do so)will eventually have seriously bad results. When you read the Gospels, Christ never wavered a centimeter from professing the true word of God. He did not care how those around him criticized. He was not afraid to speak God's truth and to let the (dire) consequences fall where they might. For those who seek to live 'in persona Christi,' it seems courage would be the order of the day, not rank cowardice. The priests of our Church have too often forgotten who it is they represent.
And at the bottom of it all is one thing: A crisis of faith. They no longer believe.
They stand in greater fear of the judgement of men whom they can see, than in fear of God whom they can't but who called them and will judge them.