Where is Linux client?

[Tanshaydar]

Firstly, neither Scraper nor me is an official worker or any kind of representative here. We both are merely working to regulate and moderate the community, which is Frictional Games official forum in this case. However, since we are not officially bound to Frictional Games or official representatives of Frictional Games, we have the right to express our very ideas.
For more information about forum staff and who they are, this link might help.

If you think an e-mail like this would help, you could've tried to contact the developers, to have an official word about topic.

It's already stated by the developers that if Steam brings Linux support, they'd likely add the Linux versions of their games into library without charging the people who already owns the game.

Be warned, this is merely my personal opinion about the case.
This was also a personal opinion and you should have learned about how all the Steam/Official Store/Different Store/Different Clients things work. You suggested that PS3/PC support of Portal 2, however you didn't answered Xbox 360/ PC or PS3 contradictions. Same thing happens on Left 4 Dead 1 and 2, you have to purchase them separately for both PC and Xbox 360. The examples you gave may be nice, but if you are to go through examples, it's very unlikely for you to be right at the end.

It's clearly stated that Linux version of Amnesia: The Dark Descent is available only through Frictional Games store. If you think otherwise, contact developers. Nevertheless you cannot force anything on anyone because you weren't aware of the terms while purchasing.