Yes, I see your point. But I was not questioning the reasons for someone taking an action, but the action itself. Perhaps I erred in using a topic that is too sensitive, and involves a psychological disorder. For that I'm sorry to have offended.
Dozens of threads on this forum have discussed homosexual orientation. Many think that it is a mental illness that is not chosen; in that respect it can be similar to bulimia. Yet would you have a problem with a discussion about the objective nature of homosexual acts?
My point is that we should still be able to discuss the nature of things, be they voluntary or non-voluntary. Certainly Parkinson's disease is not something that is chosen, yet as you have stated, it is a "disorder" in the objective sense. (Although it does not relate as well to contraception because it does not involve a bodily function that has two aspects or ends that are divorced.)
You state that bulimia is not a "disorder in a moral theological sense." It might not be sinful for the individual, but it is a disorder in the theological sense that the action the individual takes is contrary to God's design. I think I should have left out the adjective "moral" because that connotes personal culpability.
Let me try this approach: If someone eats a meal and then pukes involuntarily -- because of a virus or a mental illness such as bulimia -- there is no sin. It is an objective wrong, but not sinful. BTW, nowhere in my previous posts did I use the word "sin." My explanations were strictly about whether an action objectively complies with God's design.
Thus, if contraception is practiced in a non-voluntary way, such as infertile couples, there is no sin. But the OP's question clearly dealt with intentional, artificial contraception. This is disordered in the objective sense, and also sinful when engaged in knowingly.
I guess I should just talk about throwing up in general and leave out the bulimia. Again, sorry to have stirred things up. :blush: Merry Christmas!