Uh. What? Endorsed by Microsoft? Hell, Mozilla Firefox isn't endorsed by Microsoft, either. Microsoft isn't exactly in charge of what gets installed on their operating system. In addition, the drivers installed by Alcohol 120% (for its iSCSI CD/DVD-ROM emulation) are indeed signed drivers, and AnyDVD, to my knowledge, doesn't install any drivers. I can't speak for Daemon Tools, however, since I haven't used that in ages. No, the DRM failed because it specifically sought out these programs and failed if they were present on the system, not because they caused an incompatibility. It was a known "issue", and touted as an anti-piracy measure.
The point is, the EULA has no legal binding, and is also not an instruction manual. The presence of certain software on a PC has nothing to do with any EULA; It's the stupid design of DRM products of the day that caused these issues.
Actually, the EULA has legal binding, and it the basis on which a company responsible for releasing and selling software will defend themselves, as user agreement is mandatory. You aren't committing a crime exactly, by violating a license terms, but you are acting at your own risk from that point on.
As far as endorsement goes, we're talking about drivers, not just a simple browser. The drivers run in kernel mode, and are pretty much the only piece of software that is allowed to directly talk to the hardware. All drivers should be thorougly tested and checked, and only then signed. Just like it happens on the macs, mostly. Unfortunately, the "driver signing" is avaliable for everyone for a "small" fee, and Microsoft doesn't test everything on the drivers, they just check them for vulnerabilities. Some drivers are tested and signed, like the Alcohol 120% drivers, but since they run partly in user-mode, it's only natural for things to fail. This doesn't apply to Spore or C&C protections only. It applies to anything that may need to test the hardware, and finds odd answers there. Such as the well known (and badly implemented) Starforce protection.
Never forget: Everything might seem to work well, but if you're not respecting the program's license and documentation, you're on your own! It's just like driving a car, you're on a straight road, there's nothing preventing you to turn to either side, but if you do, it's not the car's fault if you crash!