You make it sound like a conspiracy theory but it's just rational behaviour.
Large amount of leverage / shorting / concentrated bets in a single stock => increase probability of large swings in that stock's price => bigger risk of sudden market moves => bigger risk to market makers => market makers limit their exposure.
Large amount of leverage / shorting / concentrated bets in a single stock => increase probability of large swings in that stock's price => bigger risk of sudden market moves => bigger risk to market makers => market makers limit their exposure.