"halting trades" is not the same as "halting buys only while allowing people to sell in an attempt to crash the price so our biggest customer doesn't lose money"
It is. Halting trades always produces winners/losers.
Retail investors are RH's biggest customers. They're diminishing their risk of suits they'd likely lose/regulatory scrutiny by halting buys. The SEC will more likely hit you for allowing pumps rather than preventing them.
Exchanges are able to decide what to halt (obviously since that's what they did). The SEC/class action suits are free to argue the issue, but the likelihood the suit will succeed is low and SEC intervention (beyond an opinion statement) is also low. In the investment space, retail investors are generally treated like children who need to be protected (that's what the SEC is mostly tasked with). RH will make the argument that it was protecting the children from hurting themselves and the SEC will likely go along with it (that's their assumption anyway). Fairness isn't something you generally see in trading.
