You're very specific again with which exact communities to deter but these are communities of games with very opposing views and styles. Anyone as evil and toxic you want to believe will invade our precious little game would probably become uninterested before their trial even ended, and if they stay? Well, congrats, those kinds of people already exist. They always will. Story gate isn't the magical filter that works all the time, and causes harm just as it helps.
Mainstream audience has merely been a by-product of the real target audience, and they will always co-exist with each other. And the scope of the dev's vision falls under providing, not restricting. Again, there are those who already exist that in your belief are actively going against their vision because they do not put in the time to listen to every bit of dialogue and read every text box. It exists for those who want it, but that doesn't mean it needs to be a detriment to those who would gladly enjoy every other aspect of the game. The devs have shared their wish that everyone enjoys the story provided, but they do not shun anyone uninterested, telling them to leave. You are taking their vision and instilling your own, actively wanting to push away these people if they are not in it from the get go. Gates should exist to an extent as they do filter out certain undesirable entities, and the story gate for HW has served to push against the flow of RMT into HW territories. But over time it becomes a compounding problem and that gate grows higher and higher. It's an issue/non-issue now because from ARR to HW is a week tops of efficient effort. Not desirable to everyone, but tolerable, but this was after HW was released. They did not trim the ARR story at first, and it was still as fat and unappealing in its entirety. Community feedback led to them trimming the fat and streamlining it, making it more what it was meant to be: An introduction to everything, if nothing else.