"Microsoft denied there was any backdoor. In a lengthy statement, a spokeswoman insisted that users cannot expect "privacy without good security"."
Microsoft introduces a false tautology here... "a implies b" does not mean "b implies a". I don't expect privacy without good security, but some extra security (that I don't have control over) does not necessarily mean an increase in privacy. In this case, the TPM is not under user control, it is under Microsoft's control, so it does not improve privacy. Regarding security, I can't fully determine what it does but it seems to me in reality it allows for supposedly stricter DRM (digital rights restriction) systems (and maybe stricter OS tampering detection insofar as the tampering could be used to extract "protected" video and audio streams) rather than actually working to keep YOUR data any safer than it is now.
Regarding M$'s claim that it doesn't take away user control because you can buy one with TPM disabled *by the OEM*. I'll do one better, and buy hardware with no TPM whatsoever and no Windows, thanks. Saying "you can just not buy/use XYZ" doesn't address XYZ taking away user control, which TPM undeniably does.
Regarding Microsoft's claim that TPM doesn't interfere with installation of other OSes because Windows can be told to clear the TPM -- so, won't any "naughty" OS (like a rootkit) simply nicely ask Windows to clear the TPM, then be just the same as a TPM-less system? Plus, you would then presumably risk losing use of any rights restriction-infected files you got which rely on healthy TPM operation, with the TPM storing keys or what have you.
The fact of the matter is, I can't say for certain TPM will do anything in particluar, but from a security standpoint in general? I do not want a black box processor which runs unknown code, updated from unknown sources at unknown times, performing unknown operations inside my system, and that is what TPM is.