Why the hell do private sellers never have a carfax or maintenance records?

I'm in the process of finding my girl a used car. I swear no private sellers have a carfax or maintenance records. Legit only met one guy so far who had all his records. I'm a handy guy, but by no means a mechanic... I'd have to guess your average person is even worse off. Don't people want to be seen as honest and trustful? Even if I was selling a shit box I'd still provide a carfax. It's most likely going to a young kid or someone down on their luck financially. They better know what they're getting