Is it harmful to list too specific research interest in personal statement?
I am not sure if a statement would be harmful, it will be a question of how well you appear to know the field. You are right in that you have not nearly read enough. It would be better to simply state that you are interested in such and such a field without going into depth, after all being interested is hardly a problem. If you try to get into arguing for why a field is interesting without having a good grasp of the field, you run into the likely situation that instead of primarily showing your interest, you simply expose your lack of knowledge. No-one would expect an undergraduate to have deeper knowledge about a specific research topic but if you try to argue for some field based on very sketchy knowledge, you may come across as naive. I therefore think it is better to simply state fields that you are interested in without going into specifics. If you manage to read up on a field (which would take, likely significant, time) so that you have a perspective, then such a statement would be a definite positive. Coming across as having good general skill (knowledge and abilities) is still the most important aspect.