All right, I see what you mean. I'll explain why I think there is a best method.
For a single person considering the question on their own, the best choice is limited to what's available to them. Since there are (approximately) equal numbers of men and women considering this, neither population affects the universal rankings.
But for a couple considering their birth control options, it doesn't matter on which of them the responsibility and direct benefit fall. What matters is the effectiveness and side effects. So they can agree on which is best without worrying about who holds the responsibility, etc.
So, for example, the pill is better than condoms, because it has a lower failure rate and doesn't have the side effect of severely reduced pleasure. The fact that a single woman can't depend on condoms and a single man can't take the pill cancels out, because there's one of each of them, and the couple is making the choice for both of them.
What you have described is not a "best method;" it's a compromise due to limited resources. Using multiple complementary methods will always result in a lower risk than deciding on any one of the options.
By that standard, an IUD is better than this because of the battery of Stage III and postmarketing trials supporting its effectiveness. But I disagree with your standard and find it to create a false dichotomy where there need be none.
The dichotomy exists regardless of your not acknowledging it, though. I have _had_ these conversations and made these comparisons. My current girlfriend and I switched from condoms to the pill, despite the extra responsibility for her and the definite potential for side effects, because it's a better form of contraception, period. The very instant we can switch to RISUG we will, because all available data indicates that it's better in an absolute sense.
For a single person considering the question on their own, the best choice is limited to what's available to them. Since there are (approximately) equal numbers of men and women considering this, neither population affects the universal rankings.
But for a couple considering their birth control options, it doesn't matter on which of them the responsibility and direct benefit fall. What matters is the effectiveness and side effects. So they can agree on which is best without worrying about who holds the responsibility, etc.
So, for example, the pill is better than condoms, because it has a lower failure rate and doesn't have the side effect of severely reduced pleasure. The fact that a single woman can't depend on condoms and a single man can't take the pill cancels out, because there's one of each of them, and the couple is making the choice for both of them.