Your points are valid and I agree with many of them. However, Government has no business telling anyone what they can do with their own bodies, and on private property. (Not that anyone ever owns their property since the Government always charges you property tax, but thats another rant :-)
I agree with you up to a point. However, since we don’t live in a vacuum, I guess my point stops in a different place. Not to use a rather tired slogan, but children are involved here. Children who are influenced, children who are aborted, children who have to grow up fatherless which is a well documented disadvantage, etc. So I think even a classic libertarian, considering the extensive damage done to minors, might be able to hold my position.