The main reason that curebies are dangerous is because they're usually willing to take any steps possible to convert their child to a normal one - even if there's risk to the child's health, longevity or mental state.
Curebie therapies are often quite nasty and many (most) of the doctors who support cure movements tend to fall into the "quack" category. In some cases, the curebie medical profession seems very similar to internet scams with the main aims being more monetary that social.
Jenny versus Jennifer
Just another Hollywood uninformed propagandist?
Original Biomedical Theory
Blame all Vaccines