Despite being a Dominican before, Cardinal Schoenborn's involvement with many dubious enterprises does make one suspicious. Nonetheless, I think the criticism of the YouCat's handling of homosexuality is excessive:
Implied in the words “homosexually oriented” is the idea that homosexuality is a congenital condition, not a learned behavior or a perverse life-style one decides to enter. By implying that homosexuality is “a lack, a loss or a wound” and not a decision by a mature adult to transgress God’s laws (as Scripture and Tradition say it is), YouCat seeks to elicit pity for homosexuals due to the fact that they are simply “born that way,” as it were, and thus denied the opportunity of sexual “union” that other people possess. YouCat further implies that if the homosexually oriented person “accepts and affirms” this congenital condition, he can do so knowing that God can make good of it because He “lead souls to himself along unusual paths.” Instead of telling the homosexual that his sexual tendencies are an outgrowth of his uncontrolled concupiscence and that he should pray to God to have the power to eradicate this state of mind, he is told, more or less, to accept his condition and hold God to blame for making him homosexually oriented. His only consolation is that God will make up for it by using the condition to lead him back to God. In effect, homosexuality is treated no different than if YouCat were talking about a mongoloid baby, since, similar to YouCat’s understanding of the homosexual, the deformed child can also use his condition as a “springboard for throwing one into the arms of God.” In the end, YouCat neither calls homosexuality a sin, nor does it say that homosexual inclinations are perverse and need to be remedied.
What is the definition of homosexuality? The sexual lifestyle? Or the mere attraction to members of the same sex? Nor do I see the YouCat blaming God for the disorder: "A lack, a loss, or a wound—if accepted and affirmed—can become a springboard for throwing oneself into the arms of God." The lack or loss or wound is a consequence of Original Sin, and can be explained as a bodily defect.
Similarly, with respect to the use of "demonizing" in regards to masturbation. Is it a sin? I think so. But what needs to be avoided is repressiveness that stunts the development of healthy sexuality. Now, I don't have a copy of the YouCat, so I don't know if it deals with masturbation at length or offers good pastoral advice. Maybe it's treatment is insufficient, maybe it isn't -- there's nothing within the critique showing that the paragraph is too brief.