Its possible that theres some of that. But it seems unlikely to me that thats the main thing going on. For two reasons.

One is that these kids tend to cluster in families. I can understand a family having one kid that doesn’t fit in, but for every kid in that family to not fit in? That seems a bit unusual.

The second reason is that people tend to start homeschooling young, like kindergarten (it is much more common for families to start it when the kid is very young then give it up as the kid gets older than the other way around). And I think at that age it would be really hard to tell if a kid fits in or not, so I don’t think that would be the primary reason why parents are deciding to not put their kids in school.