There's no central organized body that can regulate every smash tournament, so it's impossible to impose a formal ban on all scene tournaments that happen. The biggest player here that could have any authority over the issue would have to be Nintendo themselves threatening to drop support if the 1 year ban is not served or if a lifetime ban is not served. It actually would've been smart for the community to get in touch with Nintendo to help draft an appropiate response and to try to work together in order to strengthen the community in this time of crisis.
However - and I realize I'm going down the worst rabbit hole imaginable - I'm not a big fan of "internet justice" and "off with his head" mentality.
I'll get a things out first, what he did was horrible, despicable, a breach of trust to both his friends and the community as a whole. Being drunk is not an excuse ever and it's not even possible to argue he was just getting mixed signals due to the environment and context this happened.
His "apology" was also salt on wound that was about him and what it would do to him instead of any attempt to actually apologize, own up to the sexual assault he committed by understanding the gravity of his actions. I'm also capable of rationalizing that he doesn't speak English very well and that he was most probably completely alone, half aware of what happened and without anybody to help him sort out the situation, but it still no excuse for the terrible follow up to the actions he did.
So with that out of the way, I hope I'm not eaten alive by jumping into the lion's den, a formal lifetime ban is both unfeaseble in a logistical way and I also believe it is not also a right course of action. The 1 year ban with a second strike rule is a sensible approach to the topic because it allows for a healing period for everybody personally involved and to the community at large. It serves as a standard to adhere while everything gets sorted out. It will always rest on the community to enforce both the 1 year ban that's recommended and to actually have the trust to let him back in after that recommended period as he wont be naturally exonerated because of it. The girl assaulted along with the rest of the room involved while have to grieve and come to terms with the violence that occurred, and hopefully, with the support of the community will be able to somewhat overcome the trauma psychologically and socially. Formally or informally imposing a lifetime ban on the perpetrator will only serve as a preventive measure for this type of future incidents and might also help other people to speak up when faced with abuse, but for healing, which I believe is the most important issue to resolve out of this crisis, forgiveness has to take place. It needs to be earned obviously, where Hyuga would have to actively work for it, the girl and the others will need the time to recuperate and assess what is better for them, and the community at large allow him back after an indefinite amount of time if he helps to establish safer environment for everybody in the scene.
Formal rules against violence, including sexual violence need to be instated by all the FGC independently and jointly. Mr. Wizard is probably the one that needs to lead this, where safe environments should be the number 1 concern, above competitive environments as a priority. 1 year ban with an end of term evaluation has to take place as a minimum of the assault or harassment but never an outright ban in matters that don't directly involve the police.
I hope I'm not misunderstood as taking sides with the wrongdoers, even if I'm argueing for them, but not solely or primarily for them.
tldr; if possible, the situation should be tried to be resolved by admitting the criminal back into the community in due time for the best of everybody involved.