Because it is disputed whether it was "wrong" (in terms of effectiveness, not in terms of morality). It did achieve what it claimed. It just happened to be a rather blunt method of doing it.
The point of any medical intervention is to make the patient better. By that standard, a lobotomy is ineffective. Lobotomies "worked" by making patients deeply disabled, in a way that made them more manageable.
Speaking of lobotomies, most people think of it is a fairly major operation that requires hospitalization, but there were actually people doing them on an out patient basis. You could get your lobotomy and be on your way home an hour later, thanks to the development of the "transorbital lobotomy".
Here's part of a letter written in the mid-40s by Walter Freeman [1], a well-known lobotomist, describing this:
> I have also been trying out a sort of half-way stage between electroshock and prefrontal lobotomy [to treat mental patients]. … This consists of knocking them out with a shock and while they are under the ‘anesthetic’ thrusting an ice pick up between the eyeball and the eyelid through the roof of the orbit [the bony cavity that contains the eye] actually into the frontal lobe of the brain and making the lateral cut by swinging the thing from side to side. I have done two patients on both sides and another on one side without running into any complications, except a very black eye in one case. There may be trouble later on but it seemed fairly easy, although definitely a disagreeable thing to watch. It remains to be seen how these cases hold up, but so far they have shown considerable relief of their symptoms, and only some of the minor behavior difficulties that follow lobotomy. [That is, prefrontal lobotomy, which typically involved boring holes through the front of the skull. The ice pick operation is called a “transorbital lobotomy.”] They can even get up and go home within an hour or so. If this works out it will be a great advance for people who are too bad for shock but not bad enough for surgery.
That quote is mentioned in this classic The Straight Dope [2] column, which includes more info and cites if you want more on this disturbing topic.
> However, I see no reason for indignation at what was done in the 1940s as at that time there were no other alternatives!
So, destroying someone prefrontal functions (which is basically akin to destroying their whole personality) was an acceptable remedy for schizophrenia treatment, because, err, we didn't have anything else? How can anyone even write anything like that?
See https://www.nobelprize.org/prizes/medicine/1949/moniz/articl...