I understand how you felt, because I also kenna before. I believe, we, the photographers have the rights to demand the pic to be removed if no permission is given to the organiser to use the pic for any purpose.
It has come to my attention that some organisers just post the pictures and just put "credits to the respective photographers"... Then my question is that "do you even know who the photographer is in the first place?" Often, I give the benefit of doubt and assume that the organisers really did asked for permission and so I didn't "kpo" to OT the thread. But from this, I guess my assumption is wrong.
Understood, some models/model wannabes who are new do not know the rules and just give the pictures to organisers and such. But I think that organisers should also contact the photographers for the permission before posting them online. While there are some photographers are ok with organisers using their pictures just like that, there are some who don't. It does not take too much effort just to seek permission.