Public markets have layers of protection built in. Mandatory financial disclosures, independent audits, exchange-level listing standards, and SEC oversight. These exist because public securities are available to everyone.
Private markets operate differently. Companies raising capital through Regulation D exemptions are not required to register their securities with the SEC. They are not required to provide audited financials. There is no public exchange creating liquidity.
The accreditation requirement is the tradeoff. In exchange for access to investment opportunities that are unavailable in public markets, investors accept responsibility for conducting their own due diligence.