There are two separate issues.
One is rational investing - did shorts were extensively leveraged, should they cover at $4 or should they add to winning position.
Second issue is if what was done adhered to the legal rules.
I'm talking about the last one.
Short positions, to what I've heard, were way over 100% of the float. That means that somebody sold shares he didn't have aka sold counterfeited (fake) shares to the public.
I don't understand what you said about Robinhood and liquidity. GME shares were on 100% margin, so RH shouldn't have any risk on the book. I don't know, maybe RH do have a fine print in the contract saying that they keep all rights to clients accounts and they can do with them whatever they want if they feel like it or if their books are in jeopardy.
To illustrate this point more. Imagine you have a fully paid off house. There is some turmoil in the housing market and some entity (bank, mortgage company, insurance, borough, whatever) sells your house because they want to calm down house market by injecting liquidity or because they want to protect their books or just see it as good $ opportunity. If such behavior is allowed/tolerated by the justice system (MFGlobal) then it is bad.
That's my point.
Not to be misunderstood. I do not know details of RH situation or their clients or hedge funds involved. Maybe what has happened was perfectly legal. If so, there is no point of whining. What can be done in this situation is fixing the law. The worst case would be what is in the title of the article I linked. I hope you remember time where some voices were talking about risk being pushed to the public where profits were kept by inside players. I will be watching how RH clients react. Lawsuits is a good sign, but still I don't hold my breath.