why do you say hypdom is bad ? He always calls out predators and they say he is good
Calling out other predators does not mean someone is not a predator themselves. In fact, it's not uncommon for this to happen, as it's an easy cover and it generates a false sense of security in potential victims. Important to mention here is that every potential play partner should be evaluated by your interactions with them, not by their placement in a community. Plenty of predators position themselves in prominent places in communities, allowing them easier access to victims.
I'm not sure who "they" are here, but always be wary of subs recommending their 'tist. It's a fairly common tactic to use someone else to lure in more victims, particularly with 'tists who like to maintain a harem and push "good girls make more good girls."
For hypdom specifically because I've worked with his victims. Even were he not to be a predator (he absolutely is), his use of hypnosis is exceptionally unsafe, stripping away safeties and making use of unbound suggestions that affect the victim in many unforeseen negative ways in their life.
As with many predators, he seeks young or inexperienced victims, grooming them with false information. He does not practice proper consent, "negotiates" while the subject is under trance, and uses abusive tactics when boundaries are asserted.
Beyond personal experience, his files contain many suggestions that are immediate red flags.
If you're new and looking for someone to trance with, the best I can say here is simply to educate yourself on hypnosis, consent, D/s, and abusive tactics. Hypdom is only one predator. There're others like him, and knowledge is frequently your best ally.