Why doesn't Car Gurus find cars for sale from private owners?

Use the search filters to only see private sales.

I have tried that in the search filters. That private seller box is grayed out and uncheckable?

Probably because there are no private sales cars that fit your search criteria. CG's does not "find" cars, it is a place for people to list cars for sale.

I have my car listed and I'm a private seller. When searching with no filters, except a year range, the oricate seller is greyed out. Seems like a huge ripoff honestly.