It appears that CAcert believes it can bind people to this license in order to redistribute their public root certificate. IANAL, but there seems little basis for that. A public key / certificate is just a few computer-generated numbers: no creative spark, so does not appear to qualify for copyright protection. They are by necessity public (or else the essential cryptography wouldn’t work), so no trade secret protection. They are not a process or invention, so no patent protection.
So what’s left? Legalese blurbage protection, whereby Powerful Words impress and frighten.