As a male whose penis has been slaughtered by down votes, this really his home! I really wish people would reserve the down vote for truly offensive content or insulting comments. Down voting just because it's male anatomy is bad. It really reinforces (4) in your list above.
Then again, getting rid of the down vote could be misconstrued and cause confusion. Look at what happened when YouTube disabled the dislike count. People would go crazy and question the integrity and transparency of the community. We could end up curing our twisted ankle by cutting off our leg.
TL; DR: Love the up vote, hate the up voter.
Another great angle. Keep turning round. ;)