Hello,
I am an old TES player : Arena, Daggerfall, Morrowind.
And today, I wanted to play Skyrim, which requires Steam.

I need to download a "social software" to play a solo game ?

I need to accept a long-and-even-intrusive EULA : http://store.steampowered.com/subscriber_agreement/ (for example, section 9Cn or 10A) to be able to play my game ?
The section 10A is even more "wtf" : YOU ACKNOWLEDGE AND AGREE THAT YOUR SOLE AND EXCLUSIVE REMEDY FOR ANY DISPUTE WITH VALVE WITH REGARD TO STEAM OR THE SOFTWARE IS TO DISCONTINUE USE OF STEAM AND CANCEL YOUR ACCOUNT .
Ok, so I must agree that Steam can prevent me from playing my own games, to be able to play ?

I need to "activate" my game online ?
I have bought this game, I don't use a crack, why should I PROVE that I have bought my game ?

I need to be connected to Internet for the first launch of my game ?
Come on, it's a solo game !
Why the hell would I need an Internet connection !?

Seriously ?

I am disappointed : I really wanted to play this game.
The only thing that I can do now, is to come here, and to explain why I'll not buy Skyrim.

If you set Steam to Offline Mode after downloading and playing Skyrim once and then furthermore block Steam through your firewall, then Steam can't touch your Skyrim and you can play it offline forever. This on-activation type of DRM is used by many AAA titles.

However you will need to use Steam if you want patches.

If you want further explanation of the Steam terms you'll have to talk to their support. Basically what that line says is "You agree not to sue us for anything, ever as we're not responsible for the things we control.", which is what most TOSes say if you read them closely. Just like how you "agree" to install rootkit-like DRM into your computer for using some SecuROM protected software and other DRM like it.

My concern is not about "How to use steam", but rather "Why does Bethesda make it mandatory" ?

I don't agree Steam TOS, so I can't install/use it.
"All TOSes are the same, just click agree" is not acceptable at all.

Bethesda wanted a form of drm.

They laid them all out on the table, weighed the be benefits and downsides of each, and picked steam.

Choosing to publish a game as a Steamworks title also has other benefits for Bethesda, as a business. Basically, they believed it benefitted more people than it pissed off.

I can't see any benefits for using steam, instead of a simple-stupid cd check protection.

http://www.gamesas.com/topic/1242199-skyrim-and-steam/

If you don't use it, then you are out of luck for this game.

Please don't be short sighted and mention alternatives. Really not a good idea if you want to keep your forum account.