First, you are using the naturalist fallacy, the correct way to analyze if something ts broken or not is to determine if it is fit for purpose. Homosexual attraction does not read towards procreation, therefore it is broken.
Secondly, there is a huge rate of comorbidity between homosexuality and abusive behavior.
...Leading to procreation is, itself, a naturalism bias. Assuming the biological function is the be-all, end-all of a behavior is a
pretty damn common form of naturalism bias, because it's obsessing over the "function" of the behavior
in natural terms. Pointing to nature and categorical behavior patterns is actually very useful for determining whether or not something is an
illness in need of treatment or simply an unusual quality.
The way
actual humans behave does not support homosexuality as a
mental illness like you initially declared. Because, again, it isn't just enormous swaths of other mammals showing "sexual frustration" is a nigh-unstoppable force leading to "any hole's a goal", we see such strong patterns of it in humans to end up with
specific carveouts in law because a blanket ban proved to be incapable of useful enforcement.
Also, common correlation does not render a thing an illness, unless it can be proven
intrinsically causal. And again, to enforce any kind of policy against "toxic" relationships you need a
staggeringly totalitarian state. As in East Germany, with a massive fraction of the population being payed informants, would be an amateurish starting point. You have to go
beyond 1984's hopeless dystopia.
Because relationship toxicity is a private interpersonal matter. You have to intrude into people's private lives to take note of it. Go ahead and look at the measures taken to enforce sodomy laws in the past, and note that trying to stop in on months-long voyages was considered such a hopeless endeavor as to become an exception to them.
Right, it was their fault. Their fault for fucking their way into a disease that was utterly predictable with even the most basic knowledge of germ theory.
Actually no! Sexual transmission is a bit of an outlier condition for disease and when you're in the massive hedonistic swirl of the club "community" it gets
extremely hard to trace cause and effect. Germ theory is typically explained in terms of mucous droplets from coughing and sneezing, with sexual transmission's commonplace awareness being
specifically because of the HIV epidemic.