Lifeispassingby "of course she has judged him." You are entitled to your opinion but I do not think she has.
IF she wanted to judge him, that would be fine with me too.
We all make decisions and judgements all day about what we think is best for ourselves and our families.
There is nothing wrong with this, IMHO, in fact it keeps us safe.
Not wanting to spend time with someone is not necessarily wrong.
But she has not judged him formally in some way that is harmful to him.
"She has said she has found his behaviour odd and concerning despite it being harmless." How could you possibly know it is harmless. Sounds like you have judged him. You have judged him harmless, so that is OK?
"... ignored those who suggested other sensible reasons or disagreed with her." That's OK it's her choice. She doesn't need to agree with everyone.
But him being 'feared or concerned about' by his behaviour doesn't mean he is being hard done by. Had she put up posters or reported his handbag giving to the police, that would, of course, be unreasonable. But making a decision that you don't want to be friendly or neighborly with someone is fine.
Sadly, there are some of us who are just quite suspicious of other people. Sometimes those suspicions are right and sometimes wrong. So we all make decisions on where our boundaries are. And that's OK. It's not making a legal judgement on a person, it's making a choice on who we want to speak to.