That's a really ridiculous standard, for a few reasons:
- The standard of proof in a criminal trial is "beyond a reasonable doubt", which is a very high bar to meet. (FWIW, I think it meets it in this case). We made it that high because we would rather a guilty person walk free than put an innocent person in jail. The costs of you and I incorrectly choosing not to associate with someone are far lower. There are other standards for guilt in other cases, such as "more probable than not" in civil trials.
- A prosecutor may believe a crime has occurred but decline to bring a case for a number of reasons (limited budget, jurisdiction, statute of limitations, difficulty or unreliability of evidence, because they think they don't have a good chance to win)
- We make decisions all the time about who we'll partner with, who we hire, who we fire, based on standards far lower than this. In general it's not a crime to be an asshole but you'd never say I should wait until it's proven in court before deciding not to hire one.
There's more than enough evidence about this person specifically, and in most cases, for me/you to feel fine never associating with this person, or working with an organization he's involved with, ever again, even if a court of law never gets involved.