Homosexuality is clearly apparently a disorder of the dopamine system.
Just because this is consistent with natural law theory does not therefore confirm that natural law theory is true.
Also even if natural law theory is true, that does not prove that there is a God, nor that homosexuality is morally repugnant.
And if homosexuality is morally repugnant, it does not automatically mean that it rises to the level of a 'malum in se' violent human rights violation, which is always often punished by criminal law, in almost all cases in almost all countries. (I.e. to 'get away with murder' is thankfully rare.)
And even if homosexuals are not punished for engaging in homosexuality it does not mean that there is anything wrong going on as regards the future prospects of mankind being more moral in the future than he is today, which is more moral than he was yesterday.