A surgeon for example will be in conflict with the first basic principle of the medical profession; "to do your patient no harm". On the other hand he is also bound to relieve suffering. To most an amputation can be nothing else but something negative that will inevitably lead to worse suffering than to live in a body/body shape you do not identify with. An amputation will lead to a disability which in turn is negative. If amputation instead can mean the end of long suffering and that the individual can live a "normal" and happy life, is amputation still all that negative? It is not rare that amputation is performed when a limb is possible to salvage but the quality of life for the individual is improved by amputation. This is very much the case for the true wannabe.
This is a parallel, which can be dificult to discover and to realise the relevancy and importance of. One prominent problem is that physical pain in general is much more easy to detect than psychological pain. Also when it comes to psychological pain most people tend to put up a facade of happiness to hide behind making the suffering difficult to discover for even the immediate family. This will cause some individuals to plan or improvise "accidents" in order to force an amputation of the unwanted limb. There are several cases where this has lead to death. The desperation has sometimes even lead to suicide as some individuals feel they are not meant to live.
Much of the reasons to this can be blamed on the lack of information and support. If a person does seek help there is risk that the amputation wish is only seen as a symtom of other problems. That other problems can arise as a complication following the wish to become an amputee seems to be much more difficult to realise. It takes an incredibly open mind to find a way of thinking that avoids being a direct reflection of the own (providing you are not a wannabe) belief that amputation can only be something negative.
An individual’s right to cause society "unnecessary" costs for operation, rehabilitation etc. can and should be discussed. You can adopt both an egoistic and utilitarian point of view. Be aware though that it is more complicated than saying that the egoistic viewpoint is that amputation is right and that the utilitarian one is that amputation is wrong. The egoist does not automatically set aside other individuals rights and needs since that does not necessarily mean achieving the greatest amount of happiness for the individual. Since the total amount of serious wannabes is very small the economical loss for society (including the wannabes seeking amputation) is so small that it is not in conflict with; "greatest possible happiness for greatest possible number of individuals". Thus, granting a wannabe amputation is not necessarily in conflict with a utilitarian point of view.
Keep in mind though that the result of the arguments can differ depending on the group/population they are imposed upon. I.e. depending on if you see to society in general or the affected individual’s closest relatives and friends.
To be able to sustain an economical argument against granting a wannabe amputation you should also regard the effects on society of what can be called "legal abuse". Included here are things as smoking and alcohol consumption. This is completely legal (in most countries) but potentially self destructive behaviour.
For amputation to be an option though there is one requirement that has to be met. After amputation you have to be able to take care of yourself and be a contributing member of society. This must be established before amputation can be considered. I cannot support amputation for those individuals that seek amputation to become dependant on others.
To want to become an amputee can be seen as self destructive behaviour, especially when an individual takes action to make the wanted amputation necessary. This kind of behaviour is in many, if not most cases (except for the individual who finds the amputation in itself as something erotic) a more or less direct concequence of lack of help and understanding.
As stated in the beginning every person has his and her own psychology and it is different from person to person. I, as a person, has a very hard time accepting people who try to claim their own psychology and way of thinking is the only reasonable one. Especially if he or she is trying to force it upon others telling them they are crazy or not normal having another way of seeing things. If you tell a person he is crazy enough times he will eventually start believing it.
I think therapists and psychologists do have a very important function and can be of great help to individuals that have problems but there is a danger too. As a patient you trust this person completely and this trust must NEVER be abused or taken advantage of. The patient must not at any time become an object instead of a person. Also I turn against being forced into endless therapy and medication against my will to be made "normal". That is something that belongs in literature like "1984".
This is in no way a finished topic.