I'm suggesting that we err on the side of caution by assuming that every incident of sex between adults and children is rape. This is absolutely not an issue where we can be lenient.
You don't seem to understand why this is wrong. Let's say 5,000,000 cases of "Action X" occurred this year, and 3,500,000 of these acts were harmful, but we don't know which ones. Can we say "Welp, gotta err on the side of caution and ruin the lives of all 5,000,000 people?" No, we can't. That goes entirely against the spirit of "innocent until proven guilty."
Unless you're of Stalin's mindset, "Erring on the side of caution" isn't ruining the lives of everyone who might have harmed someone and hoping we "get 'em all." Erring on the side of caution is refusing to convict anyone of a crime unless we're sure the act they committed was harmful.
"The alternative would be requiring standards of evidence that are so stringent that the law is utterly impotent to punish serious offenders."
Proof of harm beyond a reasonable doubt is too stringent for you? That's all I'm asking for.
Objectively I am directly responsible for his death, even though I never intended to hurt him. Even though there is no way of proving that my intent was to kill him, should I not be convicted for his death anyway?
You are not directly responsible and should not be convicted.
You've evidently put a lot of thought into this, which to me suggests an ulterior motive.
And this is what pisses me off about society these days. EVERY SINGLE PERSON living in a democracy should put "a lot of thought" into EVERY issue. If you want to live in a society that ruins people's lives for some given action and you support this or sit idly by while it happens, you better have thought long and hard about if that's acceptable or not, and the arguments for both sides. I defend free speech rights for nazis, the rights of various sexual minorities, the right to use drugs, the right to gamble, and many more, despite most of these things not pertaining to my life. It should sicken everybody in a society when a law is unjust, and everyone needs to be spending a lot of time figuring out which laws are unjust.
But if you want to believe I have an "ulterior motive," I couldn't give less of a fuck. It's so irrelevant that you should have never brought it up. I could be Hitler and my argument would have the same merit as it would if I was Mr. Rogers. An argument stands on its own merit - the person making it is irrelevant.