Because other Steam groups are just too mainstream.

We worship the Radical Hipster God as the true opposite of the mainstream. We worship the Radical Hipster God as the true face of gaming. We worship the Radical Hipster God as the one and only intelligent, and sensible being in this world of mainstream and stupidity, O great one, we hail you as our only God, and as the most important being. Bless us with your radical knowledge. We will mock the world and enjoy video games under your knowledgeable supervision, lead us to superiority above all.

This pledge must be taken by all our members, and worship of the Radical Hipster God must be observed for life. (Please, if you are religious, do not take offense, that's just too mainstream.)

We are the most elite of the mainstream hating, gaming, hipsters you can find on Steam. If you believe you should join us, screw off, we choose whoever the **** we want in our group, and there's nothing anyone else can do about it. We are the supreme hipster Steam group. There's no argument about it, yerks.