Perhaps I'm misunderstanding, but

There are several very reasonable objections to treating any condition with drugs, whether it be a classical disease like cancer or a marginal condition like alcoholism. The drugs can have side effects. They can be expensive. They can build dependence. They may later be found to be placebos whose efficacy was overhyped by dishonest pharmaceutical advertising.. They may raise ethical issues with children, the mentally incapacitated, and other people who cannot decide for themselves whether or not to take them. But these issues do not magically become more dangerous in conditions typically regarded as "character flaws" rather than "diseases", and the same good-enough solutions that work for cancer or heart disease will work for alcoholism and other such conditions.

seems to summarise to:

(1) Medical treatments (drugs, surgery, et cetera) for conditions that can be treated in other ways can have negative consequences. (2) But so do those for conditions without other treatments and we use those. (3) Therefore: we should not object to these treatments on the grounds of risks.

I'd question the validity of this argument. Consider a scenario where there are two treatments for a condition: A and B. A has lower risks than B. Where is the flaw in the following argument:

(1) Treating the condition with B has risks. (2) But the treatments used for other conditions have similar risks. (3) Therefore: we should not object to B on the grounds of risks.

The problem with the argument is that it draws a false analogy between this condition (where there is a lower and higher risk treatment) and others where the only treatment is of similar risk to the high risk treatment for this condition.

I'm not saying the people with conditions like obesity shouldn't get medical treatment: there are compelling advantages to it, such as the decreased amount of effort involved and faster progress... But I think that this argument isn't valid.