To be more exact, this self-critique is probably appropriate for a certain subset of Catholics only: conservative, orthodox Catholics. The problem just does not apply to nominal Catholics or very loose Catholics, although the problem may, in some cases, have contributed to such people's distancing themselves from Catholic teaching.
The problem is this: the brooding, legalistic conscience (better known as scrupulosity in traditional language). The problem within the problem is this: according to Catholic teaching, the conscience is the voice of God. We get into trouble when that voice is replaced with our own, let me be frank, neuroses and anxieties. Again, surprise of surprises, we see the need for the biblically revealed charism of discernment of spirits: when is the voice that I may think is my true conscience (the voice of God) instead a false conscience (the voice of my own defect-filled personality and assumptions).
This type of false conscience not only burdens the person bearing it, but it ends up burdening others and, as noted before, scaring people away from the Catholic faith. If you find someone who is too hard on others and thus pushes them away from the faith, you are more than likely to find someone who is just too hard on himself or herself. Being open to the unconditional love of the Trinity is a prerequisite to releasing that same love to others. If we are closed to receiving that love for ourselves, then we will not be to open to granting it to others.
Often, false conscience is seen when we mistake conventional, bourgeois values for Christian values. If we measure Jesus' life and sayings by bourgeois values, he certainly comes short. For example, he urges people to put God before family relations. That would not go down so well with many conservative Christians, both Catholic and non-Catholic. He also is deeply suspicious of those who like to flaunt their piety in the way they dress and act in public. That critical view of outward, showy piety would not go down so well with many who seem overly interested in the latest clerical garb and frills. He is also not fearful of ignoring socially accepted boundaries when it means helping the other. He speaks alone to the woman at the well to the scandal of his own disciples. He associates with those viewed as collaborators with the Roman (enemy) occupation. He associates with the worst, public sinners in order to change them. He multiplies food for the crowds even though he knows and says that some will then just follow him to get the physical food and not the spiritual food. He takes risks.
That personality--open, daring, full of life--is the opposite of the brooding, legalistic personality for whom God is, for all practical purposes, a neurotic with an obsessive compulsive disorder. Yes, we tend to create God in our own image, rather than letting the Gospels reveal Him to us. He is very different from many of us. He is just not uptight. He created all the marvels of the universe and sustains them in continuous existence. He is not intimidated or bound by the little things we magnify into a false importance simply because we are full of fear, self-doubt, and even self-hatred.