Oh I agree it would be appropriate to involve a manager. But given how horrible the situation is in Haiti, people might not be thinking clearly about it. Emotion can really cloud how people respond and may have made the situation even worse for Kimblee.
Back in the 80s, I was in a fast food place in Port Authority, grabbing some lunch before a bus trip. A rather disheveled person dressed as a nun was going up to people at the tables to collect money. A manager asked her to leave. And people from all different tables were yelling at him about how dare he ask a sister to leave! Fortunately, there was at least one cynic in the store. Correction, one vocal cynic, I was a cynic but a silent one. She yelled out, "how do you even know she's a nun." Which was pretty much my thought and why I said, "no, thank you sister" when she stopped by my table. After the vocal cynic's comment, people were yelling at both her and the manager. I had finished my lunch and it looked like it could get ugly, so I left.
What if the manager were blinded by emotion and criticized Kimblee for reporting the person to the store? I agree that would be very wrong, but it is a possibility and since the confrontation really bothered Kimblee, I don't know if such a confrontation would have helped. Even if the manager was supportive, other people might have criticized the manager. Or if the complaint was issued verbally or within the sight of other shoppers, they might even turn on her, which would have made an awful situation even worse.
It seems like Kimblee didn't want to deal with any aggression/confrontation, so that's why I suggested the "I've donated, thank you" response. If the person persists, you can ask for a brochure or a card and say you'll keep them in mind in the future. And then you can check the various resources to see if they're legit.
If they're legit and being aggressive, you can report it to the store and charity.
If they're not legit, you can report it to the entity which govens charities in your area. For the USA, it's usually the state's Attorney General's Office.