What would make some parents do that is, I'm thinking, their own need for counseling. News flash for many people, however: Parents who try to do that, and parents who are fooled by their kids into believing that they're accomplishing their aims; are clueless with regard to how most children/young people (even old people) are; and that it is that there's a whole lot of politely listening in order not to fight and/or hurt someone's feelings. In other words, at least in American culture, what can appear to be what you've described is often just that - appearance.
As soon as the person who has little choice but to put up with the overbearing, misguided, sometimes even abusive, behavior of the parent(s) that young person will, as they as say, "be outta here".
Many young people in such situations will do what they think they have to do while they're biding their time and aiming to be free of the parents. Unfortunately, for some, they may end up going through motions longer than is healthy for them - and all because (as is the case with so many people who find themselves being "emotionally bullied" - the young person worries about not hurting the feelings of the clueless-but-misguided/overbearing parents who either believe they're doing the right thing for the son or daughter or else who are just too "emotionally muddied" in their own head that they don't realize how toxic and destructive they are.
In fairness, most parents mean well. They just think they know more about life and/or their children than they realistically can know about anyone who is not them. Being a parent can fuel narcissistic tendencies in the "wrong people" in ways that are far too numerous to list/explain here. By the time a so or daughter is, say, 20, that parent has had a whole lot of time to be fueling/feeding his own narcissistic tendencies toward the child, and with regard to his own "estimation of how wonderful he (the parent) is".
Not all parents have a very good grip on their own ego and/or perspective in general.