Well First off,
About the opening observations, It's interesting how relentlessly defensive about anything Gamers are.
This does not only apply to games but also, genres within games, paricular franchises, brands and any slight difference that could generate preference. Anything can seemingly turn into a life or death personal crusade.
Maybe this is a social situation, not only a gamer thing. I've come across way too many people defending and attacking theories, ideas and beliefs, that dont even directly affect them with an impressive grudge. There seems to be a tendency to a very entitled, outgoing vocal behavior, tied in with the current media exposure available to everyone.
I mean, to be honest I wouldn't be writing this if I didin't think in some level that my opinion matters, and that I have something special and different to say. And we all have that very individualistic rather post-modern Disney induced illusion and hope of self importance.
The immediacy of information and the comfortable protection of non-personal interaction in modern communication also enable this perception further. We can have very extreme opinions and express them with little fear because, chances are someone else will agree, and anyway, it wouldnt really affect your "real life".
I guess this is all beside the point, but it does explore the type of reactions and actions we are seing when anyone or anything challenges our own status-quo (which is obviously TRUTH because I'm me, Right?).
Anyway, about the issues that games bring, I suppose we have to go back to the same old as time question, what came first?
Let's consider today that almost every teenager has some amount of contact with videogames. Videogames are not exclusive at all, and they are becoming less and less so. Completely "mainstream normal" people today get together and play games, as a totally acceptable activity. Of course this players are considered less "Hardcore", and I'm assuming we consider the possible negative effects on them negligible.
So I suppose the problem comes with players that would rather play games than experience other types of interaction. And end up denying and avoiding "real life experiences" in favor of fiction.
Thing is, introverts have existed throughout all human history. People have used Books, Movies, Comics and really any form of fiction as escapism. And to be honest, all those problems you list CAN exist extending from an addiction to any of those mediums.
Can games be more immersive, addictive and consuming? Possibly, since they are a lot more inviting and simple to get into than other formats. But the potential still exist in of the formentioned mediums. Many people in one way or another use all sorts of fiction as a "mental paralytic" and avoid intimate or community experiences, allowing them to experience a more controled (albeit "fake") situation.
I am an introvert, personally, And WAY BEFORE I had any contact with videogames, I used drawing and reading to distance myself from a lot of social contact. Today I play a lot of games, and I am very aware that I'm not an overly social person, even though I don't have any particular issues with people, I am just more reserved, but I would not directly blame videogames for that.
Of course I think that the easy accessibility to the medium enable more people that may be prone to an "antisocial" behaviour to actually approach games (and get stuck on them if not supervised). But once again, Schizophrenics will be schizophrenics, Obsessive compulsive people will behave obsessive compulsively. And in any situation these unchecked disorders will find ways to express themselves, and ultimately hurt the person.
I'm not denying the responsibility of games though, a lot of them don't help expanding the range of interaction options that a player has. But also as far as my experience goes, I have observed that there is a definite effort going into spreading the range of intelectual, emotional and inter-personal engagement through games.
Even the existance of the nintendo wii, with it's profoundly "social" approach, or the how popular the casual mobile market has become show that games are no longer such a defined and enclosed activity.
Experiences such as Journey shine a very different light on what we can expect of games, actually involving the player and asking extremely interesting questions about storytelling, about how our emotional predisposition and our behaviour can be modified through the range of options available to us, about violence, and about what companionship actually means today.