The EULA does not actively try to HINDER you doing stuff you may not be allowed to, it simply states that you are not allowed to do it.
From my understanding (important words, those), DRM is meant as a hindrance for those with a license to redistribute the data to people without a license and for the latter to use said data. No such measures are taken with games sold through GOG, all you get is a statement of "please don't do this, mmkay?" but nothing actually tries to hinder breach of the applied EULA.

That is correct, although if you buy a game from a store that has the EULA only accessible after you buy the game, or not accessible in any way at the place you buy the game from it's usually not binding since you made the purchase before they tried to make the deal, and the only way to play the game is to click accept.

And you never will . . . on GOG or elsewhere

The game is not permanently bound to you in any way. The service that provides downloads of the game is.

Management is the M in DRM. GOG packaged programs have no means to enforce the EULA. If I sell my Steam DRMed copy of Half-Life 2 to my brother, the program will refuse to run. If I sell my GOG copy of Blood 2 (don't do this!), it will run just fine.

So... Can I say that we at least all agree that the definition of DRM is insanely murky and open to interpretation? :p

Are you tricking us into actually agreeing with you for once? I mean isn't it a rule here to disagree with you no matter what?
So... no.
/jk
Yes, it is although Snickersnack sees it the same way I do. It's evil for customers and remotely decent for the corporations I guess...

If you aren't allowed to modify and redistribute the program and/or modification or redistribution has deliberately been made difficult for you (by, for example, not including the source files), then someone is actively trying to enforce their copyrights.
Again-again I'm not trying to suggest DRM is inherently baaad, m'kay? I don't see any reasonable alternative.
It's a euphemism invented for the sole purpose of making "copyright" more palatable, so yes and no. You're not meant to understand what it means, but it isn't open to interpretation.

I just realise one thing: Why console games don't have those long-winded EULA like PC games? I only have DS games here, but when I looked into their manuals I couldn't found any sort of EULA, either. Or is the EULA 'embedded' with the console itself?

I'm not sure what you're saying. If that's a definition for DRM, it would cover music over the radio (copyright encumbered, no lyrics, no sheet music, only one use unless bootlegged, etc) .
It would be silly, but you could provide source code with a DRMed program.
It's just a tool, nothing more. Now crapping on customers ...
???
DRM is access control. You can put DRM on a public domain work.
Copyright is plenty palatable to the Free Software Foundation. In fact, they depend on it.

Not quite, DRM is Digita RIGHTS Management, it is only DRM if it restricts your RIGHTS. I can make as many restrictions I want to things you aren't entitled to, I can even require your computer to have an internet connection in order to run the game and have it not be DRM, so long as I don't do anything to your rights.
For example, where I am in Canada we have the right to:
1. Modify a program in order to get it to run, this includes removing disc checks, cracking the game, etc.
2. Make a copy for archive purposes.
3. Re-sell the software, so long as you sell every copy you own to the same party, or destroy every other copy.
Note number 3. It is what makes gog DRM, it is impossible to re-sell the game legally, because it is tied to your account, and you can't legally sell your account. Copy protection is DRM, the EULA is DRM in that you are signing your rights away, and gog is DRM.
CD keys, required internet access, disc checks, none of these are DRM so long as they allow you to do everything you are legally entitled to do.

I must say, the sheer amount of mental acrobatics being performed here is quite impressive. It always amazes me the amount of time people will spend quibbling over definitions just to avoid discussing the actual concepts behind the words being tossed about.

i shall purchase a drm-free game from this website and would probably not play it till june/july.
seems like a good plan :D

While I suspect that was just an attempt to assert superiority over the "lesser" people and the like, that is actually the big problem with this.
How do you discuss the concepts and problems behind something you can't define?
Half the people here think DRM is just something that inconveniences you. Fancy that up however you like (restricts your rights, affects you after the initial purchase/download, etc), but that is what it boils down to.
Another half (the two halves are not mutually exclusive) feel that DRM is inherently an evil plan by the big mean companies to steal our monies.
And the third half are borderline anarchists :p
Oh, then there are the few people who just admit that DRM is a complete catchall, which then angers the other parties and leads to long discussions like this. If said few people were more intelligent, they would stop rubbing the vagueness of the term in other people's faces. But so be it.
Let's say we discuss the problems with Activation-Model Securom. We all agree that is problematic until we remember that you have the same thing with Steam (but with fewer activations and the like). And it stops being as much of a problem (even though having to activate on every install is a lot more annoying, at least as far as I am concerned).
So that basically leaves us with discussing the actual merits and problems of each DRM-model, which doesn't work, because people have their own personal hatreds based on things like regional restriction and the companies behind it. Then the pseudo-anarchists and the conspiracy theorists come to explain the "fact" that DRM is only an evil scheme by the Evil Corporations to screw the end user over (which, while plausible, is still only arguable :p).
Nah, the only way to ever have an "orderly" discussion on DRM that can actually be productive will be to either properly define DRM, or to make a new term that doesn't have such negative connotations.