It’s stock manipulation. The SEC made a nice PowerPoint PDF that outlines what stock manipulation is:
https://www.sec.gov/files/Market Manipulations and Case Studies.pdf
Yet it’s not enforced. Hedge Funds that are short on some of these stocks are not in a good place. And they can’t leave. They cannot close out of their positions without getting margin called. And they can’t let it go up without being margin called.