YCombinator.com and most Godaddy DNS are hijackable by new Cloudflare's tool (cloudflare.com)

email hn@ycombinator.com if you want to reach the admins

Uhh. No. This tool just explains some of the security benefits of certain registration settings. This doesn't mean what the OP thinks it means. Yes, someone could point ycombinator.com to some other server if they gain access to the account at the registrar.

Does anyone know how to make GoDaddy add the Registry Lock lines?

    Status: serverTransferProhibited
    Status: serverUpdateProhibited
    Status: serverDeleteProhibited