Afraid ECDSA and particularly the curve used is already cracked by the NSA or has backdoors. Afraid that SHA is not mathematically "proven" to be cryptographically safe.

etc. etc. etc. Basically even though they are engineers, little time has been invested to understand the cryptographic functions used so they default to MSM and FUD. I can't say I understand them fully, by no means, but I try to learn a bit more about them every day.