I feel like interaction with other cultures it's part of what makes well-rounded adults.
Homeschooling and private school and creates a siloing effect
While that can happen it doesn't have to. Homeschooling itself offers opportunity to try unconventional methods that public schools cannot.
Your experience of homeschooling no doubt mimicked the traditional public school approach and so offered the negative aspects of public education without the parts you enjoyed. But many homeschoolers can learn at their own pace, engage in activities in association with other homeschooling families, and enjoy a much broader and extensive learning environment than is offered in public schools.
And, if I'm not mistaken, homeschoolers won the National Spelling Contest for a number of years.
I realize this wasn't your experience so your view is limited and negative. I'm not denigrating your view. Merely trying to inform it.