That should give you the vector to look into - the question of assimilation and the other has been adequately discussed elsewhere.
As someone who was homeschooled, and would quite happily at least try to homeschool my own children in the future, I do agree with this statement.
Nonetheless, I don't necessarily see it as a strict negative. Yes, initially after finishing my secondary education there were some difficulties with integrating specifically with my peer group (but not with other age groups). This took at least a couple of years to overcome to a sufficient level that I "passed" as a normal person. A lot of this was not social ability per se, but more to do with using the right vernacular, dressing to match my peers better, and avoiding certain social faux pas.
However, positively as an "Other", I am advantaged in some ways.
1) I fit in better with other "Others", like immigrants and their children, racial minorities, odd and strange people, and so on. Because I was/am one, they are "my people", even if I can easily pass as not-Other.
2) Learning to assimilate means that I can easily assimilate into different cultural contexts more easily than those who never had to. I can fit in with a wider group of cultural contexts and adjust quickly and easily.
3) I have a different perspective on some aspects of society that is not necessarily better or worse, just different.
When you add that up to the other benefits of homeschooling, I'm not sure the negatives come near to discouraging homeschooling. However, my experience is not everyone's experience, and I understand that some people remain stuck as Other and suffer for it. I also can't say it felt particularly good to be Other and unable to pass as normal, in the interim. In the long term, I don't know that it mattered that much.
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I feel compelled to note that the common idealisation of being a maverick, odd-ball, elite hacker on the edges of society and so on that is common enough in tech circles is not necessarily an advantage or something I am advocating for. There's nothing wrong with being ordinary, and being unusual often or typically works against you. I wouldn't homeschool my children to make them unusual, and I don't think we should glorify weirdness as superior. I don't consider my experience as being an odd-ball on society as something that makes me superior; if anything, it was for a time an inferiority to be overcome.
There are meaningful advantages. But on balance - again, it's been some twenty years since I was homeschooled - I've found that being an Other to be painful, repeatedly. I don't believe assimilation to have ever been finished for me. I think the alienation and lack of normality has repeatedly hampered my interactions with mainstream society, to some degree or other.
This has material consequences in all sorts of interactions in relation to "social fabric" things. Some of those consequences are trivial - preferring different media; some are profound - things relating to promotion and so forth WRT soft skills.