summitus: [...] And if I buy the physical copy of the game and give it too my friend is that also mean that he had pirated the game even though I gave it to him ?
I think the problem is, your friend will still have access to the game....Anyways, it really doesn't matter if you feel it is right or wrong. What matters is that GOG tells you in its rules what is acceptable or not to them. It is their company, their site, they set the rules, whether or not we think they are right or wrong, doesn't matter, if one wants to use this site, they should obey the rules of the owners of the site. I hope that clears some things up for you and your friend.
EDIT: Well, I guess the next D&D character I'll be rolling will be Lawful ;)