Get your kids to do extracurriculars where they'll meet kids from lower-income households. It'll make them able to relate to them and understand them better.
And when you're there, talk to people. Not just ones who will help you climb the social ladder in whatever elite clubs and orgs you want to join. People of all stripes. It's a much more diverse group in every way than the author describes.
Honestly it sounds like the author was elitist and sheltered as a kid. And now they've realised this, but have decided to blame it on their university rather than deal with the fact that it was their own personal fault.
I spent my 20s working in STEM and living in between MIT and Harvard which meant that a large portion of my social circle was drawn from those schools. I see where both sides are coming from here. On one hand you're right in that there were also plenty of people in our circle who came from very different backgrounds. By and large these were normal people and not the sort of socially awkward weirdos the article describes.
On the other hand the article rings true at times. The bit about worrying about their occupation due to the 20 year reunion, I heard that exact thing countless times. The lack of recognition of the second chances to succeed or that they have a ridiculous social network that others do not was also a big thing. And through it all there was always a certain baseline, well, elitism. It was almost never direct but it was always there. It wouldn't be directed at the rest of us but you'd hear it amongst themselves, "I can't believe a Harvard graduate is doing that" when "that" is something that their good friend also does. That sort of thing.
Whether these extracurriculars would expose you to different ethnicities and world views is dependant on demographics.
I have never heard of community service as a requirement to graduate high school. (No school in my district had this requirement.)
Granted, I understand your overall point. It is becoming increasingly difficult to be accepted by "elite" colleges. In fact, I had applied to nearly 12 colleges that were highly respected in Computer Science and was rejected from all of them.
http://patch.com/california/redlands/2016-top-100-public-hig...
None of the top ten schools on that list seem to have a community service requirement [0].
There doesn't seem to be a hard and fast rule regarding which schools do or don't have a community service requirement. Mission San Jose does, but Lynbrook does not.
[0] As determined by a quick google search for each to locate "$SCHOOL_NAME graduation requirements", followed by a quick scan for anything outside of required course credits.
Either way, your statement about the top 10 CA high schools is false. I attended Granada Hills Charter and San Marino high school (#1 and #7 respectively) and both do absolutely require community service. San Marino requires 40 hours over four years [1] and GHCHS requires 20 hours per semester [2]. A friend at Miramonte High School didn't have to do any community service but I recognize many of the schools on this list and can confirm they require community service. Searching for "graduation requirements" just gives you a list of credits you need but doesn't include community service or disciplinary rules for graduation.
[1] http://www.sanmarinohs.org/apps/pages/index.jsp?uREC_ID=2241...
[2] http://www.ghchs.com/UserFiles/Servers/Server_20226865/File/...
And to be fair, I don't think charter schools should be lumped in with the rest of the public schools, but that's probably just my opinion.
[0] http://cc.sduhsd.net/Counseling/Community-Service/ [1] http://www.lhs.fuhsd.org/resume
But sure, it looks like my naive search approach is inadequate, as it for the most part brought up credits (as you mentioned).
It's a general state-wide requirement in Maryland, for example. See http://coursebulletin.montgomeryschoolsmd.org/Home/Introduct... for reference.
And that's been the case for at least 20 years now.
But everything in life is a choice and if the author is so self aware of this "disadvantage", they have simple paths to fix it. Instead of people making more home food delivery start-ups, create one to help underprivileged get access to education or healthcare, etc.
The key take away for me is that if you decide to live your life based on someone else's terms, you'll never be truly happy. Create your own path on your journey.