SB, this isn't directed at you, but at the sentiment you're expressing above.
Assuming you don't mean "it doesn't affect me because I don't care about Diablo 3", how are you going to feel when after vanquishing a particularly hard mob only to see a message that informs you that your game will reload to the start of the level because your internet connection missed a [strike]bit[/strike] beat along the way?
Although I was conscious about this, it wasn't until late last month when Steam screwed up a maintenance update and locked me and several others out of playing our single-player games that I fully realised just how preverse a system that is supported by a constant internet connection can really be. I went 19 days without being able to play games I purchased, that I was in the middle of, that were single-player because of a mistake by the content provider that can always wave in your face an EULA that says they are under no obligation to guarantee the availability of service.
My router (don't know if through my ISP or by firmware alone) resets every 24 hours, regardless of whether I'm in the middle of a videocall with Indonesia discussing a cure for cancer or downloading [strike]pr0n/warez[/strike] linux distros.
When I used to play MP Team games (BF2, ETQW, etc.) I'd forcebly disconnect the router before my play session exactly so I didn't have a reset in the middle of a match when I was about to rain a fiery death on someone's backside.
How about [strike]fools[/strike] people who play through a wireless connection which is proner to loss of packets, resets, whatever? You're playing in an internet cafe (do those still exist?) and suddenly the owner decides to boot everyone off and restart their domain server.
Again, their argument that this is to protect the integrity of online play is completely demolished by the fact they could always give players the choice at character creation of whether to keep a char always online if they wanted.