I actually haven't seen a lot of this. There are over 8000 people on that Facebook page and for people who haven't tried to wrangle an internet circus before, it has been overwhelming for some of the admins. They are being harassed privately, and trying to work full time while policing the page so a little crankiness Is to be expected. Still, people don't listen and yesterday were posting a bunch of crazy stuff over there. They did trim back the number of admins and it seems to have helped but it's going to be hard to stop the influx of not so helpful advice.
I know the family has complained about people using this situation for PR for other groups, but we don't know what those circumstances are. I don't think they would turn away anyone that also has a missing loved one and are trying to help, unless that person was causing more trouble or work. Let's face it, these things draw all sorts out of the woodwork, and not all of them are helpful to the situation. They can use the help, but not help that is going to distract from their goal of finding Kristy.