I've been around SNMP for almost my entire professional life, and I can see why people make these claims -- in fact just the other day I noticed I'm still listed as the contact for the enterprises.567 -- I was the original registrant and haven't worked there for over 14 years.
Basically they boil down to
1. SNMP software being written by people who do not understand the Internet or what standards compliance means.
2. The SNMP agents are running on network components, generating junk output that no-one really looks at.
3. Network engineers do not understand programmers and can't recognized non-compliant output
4. The output is interpreted by programmers (see #1 above)
5. This is rendered by network management applications into something that humans act upon.
in 2002 ~11 years ago SNMPv1 was moved to 'historic' status and SNMPv3 was moved to STD status: If you have equipment less than 10 years old it should support SNMPv3, yet it's still not that common for engineers to configure it up.
I can see why in the face of inertia I can see why Microsoft, or any other company with their pull, wants to move to something they 'understand' so they can sell more SCOM / whatever. But this '