Because they are not passing those investments to retail? Everyone involved is either (1) accredited investor (2) involved in the running of the business.

The contracts themselves are not traded directly. If they were they’d obviously be a security.

Large record labels do of course have stock in their companies which is a security and is traded.

You can buy shares in music royalties.[1] Those are investments registered with the SEC, and the issuer is an SEC-registered broker/dealer with FINRA regulation and SIPC insurance. Your song portfolio may be a dud, but the company behind this has to account for the money they collect, and people will be held responsible if it goes missing.

[1] https://www.songvest.com/how-it-works

The page literally says they aren’t registered. The copy is made to look like they are.

No, they registered their offering. Here are all the documents filed with the SEC.[1] There's a prospectus, and annual reports.

[1] https://www.sec.gov/edgar/search/#/q=SONGVEST

Filing stuff on EDGAR isn't registration under the Securities Act.