Why Ranked in lower elo doesn't matter to Riot

So Riot resets high end elo. They didn't to anyone below this magical BS line they created. If you are not master's and above you don't matter to Rito. Why their reset and not everyone? The only answer is Rito doesn't think that if you live below this magical line into Mordor it isn't worth it. There is NO excuse they can give which PROPERLY explains this. Yes they have given excuses, but none that properly explain the magic behind screwing over a majority of their playerbase.