This really is just arguing semantics on the internet, one of the least interesting activities, usually.
I can almost guarantee that Paul Graham has read material produced by companies, which contain information on a business' plans and current status, including financial.
If you don't want to call that reading a business plan, that's fine. But it's really besides the point.
Further, he's denied that other people have read business plans or balance sheets for him. That's also very likely false. Reviewing a balance sheet is an elementary part of due diligence, I'm sure that many startups have been funded based on a conversation over coffee, but at the scale of PG's investments I don't believe he's never been involved in a transaction where his side has had someone due the most elementary due diligence to confirm founders' statements, e.g. by reviewing a balance sheet / income statement, which he has denied.
I mean hell, he's been director of various companies, typically you're required to co-sign at least annual financial statements as a regulatory obligation, sometimes audited, which always include balance sheets. Come on. Just restate your point: I don't focus investment decisions on traditional balance sheets at all, but rather on conversations with founders.