Well one because I think there is a difference between "hardcore" gamers and core games. I've always seen the hardcore gamers as those who rose during PS2 generation and more notably the 360 era. They see gaming for what has been during that time and think only certain kinds of games are for them and that's what it should be. Also thanks to the internet they are pretty vocal about it and flood the forums. Therefore they want the action games with shock value in them.
Now when it comes to core gamers, I see these as your old school gamers. They very much so are a niche gaming community and like the games you were kinda describing.
However the "hardcore" gaming community you were talking about could be essentially associated with any mainstream gaming userbase you think about. They are your Madden, FIFA, Call of Duty, Cabela, and even Mario and Wii Fit gamers. They define the mainstream. They buy what's popular and what's big. Just sometimes they like to make a split in there by those who buy the more gory ones and those who don't. And then they are pretty zenophobic about the new gamers coming in.
The point is gaming is being split way too much by these factions and unfortunately the media is driving it. Retailers and publishers are also using it for good PR from those user bases. And I think amidst all of it, core gamers like a few of us in here, are kinda getting pushed aside from it because we aren't many anymore. I still blame the internet for most of this because there is no justice on the internet... only illogical opinions with a few logical ones mixed in. It tends to polarize the factions and that's what we are left with now.
Maybe soon we can all set aside our differences and just call ourselves gamers but I doubt will happen. Everyone just has to be an elitist it seems and think their gaming preferences are better than others.