This is nothing like the relatively common trading halts imposed by the exchanges under various circumstances—-which halt all trading, not just buying.
This is a specific broker—-one with direct financial ties to this trade, by the way—-totally shutting down the ability to enter an opening order for a specific ticker. Pretty unprecedented artificial suppression of demand.
Several did it. I heard WeBull did the same. I know I got a TastyWorks notification when they did it (and a little while ago when they turned it back on).
The more I hear, the less convinced I am that RH in particular did something nefarious.
No this actually happens and it's not the first time (see retail investors vs dot com bubble for more). RH likely has lawyers that referenced past instances of SEC action and decided to take the path of least resistance.