These always have been, and always will be illegal. The difference now is the SEC will be hunting you down and fining you/placing you in jail. I'd recommend not joining these, because they're shady as hell, illegal and you'll be left holding the bag.
What are you talking about ? Pump and dump groups arent illegal although some of them are shady and only wants to scam you if ever you fall in their trap. mostly those paid pump and dump groups that proclaims to be premium are the ones that is suspicious. .
Overall , i would not recomend joining these groups because they wouldnt still assure that their predictions are legit and accurate because the market is uncontralble due to their volatility.