This kind of long clause rarely comes at the beginning of a sentence, but at the end like "It is a positive thing that parents are...". Is the reason to emphsize the clause as it's something the writer wants to put stress on?
p/s BTW, do you call "this long clause" "true subject" and "it" "false subject"?
pp27)Some parents write resumes, attend job fairs, and chat with career counselors for their children. These are extended forms of helicopter parenting, which is a term meaning parents who hover over their children's lives from childhood to university. To want the best for a child is only natural. But according to some experts, helicopter parenting can prevent young people from developing their self-conficence and independence...That parents are actively interested in their children's lives is a positive thing. That today's youth are open to receive advice is also great. Nontheless, experts insist that it is important for parents to be aware of the boundaries that they shouldn't cross.
You are correct. It is something the writer wants to put stress on. Also, it fits neatly into one of those classic, and very commonly encountered, elements of English communication: what is sometimes called the "Rule of Three". This is where just about any list is always made up of three elements - with the final one having the most emphasis. It's the "Good, better, best" syndrome. In this case, it's "....is a positive thing. .....is also great. Nonetheless, experts insist that...". And you know that the writer wants to place most emphasis on parents not crossing boundaries.
Sorry, I can't help you on your BTW question.
I'm not a teacher of English, but I have spoken it for (almost) all of my life....