People can answer the poll in two ways and I suspect that the poll results are showing this. The first way is to answer on the basis of desire and compatibility. The second way is to answer based on awareness of statutory rape law and societal customs. If there was no such law in place, then you'd be getting more men voting affirmatively.
As someone pointed out, there are a few factors in play here. First, is the issue "Do you find young women sexually appealing and want to have sex with them?" and then there is "Would you want to be in a relationship with a young woman?" and then there is "Considering the laws, is it worth the risk to have anything to do with the young lady?"
Evolution has wired the brains of men to find neotonous women sexually appealing. We're not talking prepubiscent here, at 16 these girls are in that stage of being half-girl and half-woman, and some are past the half-way mark. These girls have a different form of sexuality than more adult women. It's the innocence, the non-jadedness, the gullibility, the puppy love devotion and I'm sure other factors too. Most of these behavioral and physical traits are not turn-offs to men. They're not stable traits upon which to base a relationship, but they're well within the range of traits that men find attractive in women. The woman qualifier here is key. These girls have to be able to appear as young women, not prepubescent girls - normal men aren't wired to find little girls sexually attractive, so a late developing 16 year old is going to be seen by men differently than an early developing 16 year old girl.
Look back in history and you see that girls this age, and younger still, were getting married, so that speaks to the fact that men were finding them attractive and suitable for marriage.
The reason we have statutory rape laws is that these young women/girls are easily manipulated and older men are more sophisticated in how they can manipulate these young women. That though doesn't mean that all young women are manipulated easily and that all men are planning on manipulating these women. Some men are skeevers and some are men are honorable. Some girls/women are immature and some can handle a relationship. The very basis of a relationship is to move forward together and refrain from selfish manipulation, healthy relationships that is, so I don't see a reason why such age disparate relationships MUST fail. A professional colleague of mine is married and in such a relationship with a large age difference. She was in junior high school (I can't remember her exact age) and he was a graduate student in his mid-20s) when they met at a dinner at some cultural center and they knew each other for a few years, and he knew her parents, and they were all friends. They commenced a romantic relationship when she was a junior in HS. Then they got married after she graduated. They both made sacrifices. His career had to take her university experience into account. Her university education involved a few transfers and no sorority parties and no dorm living. They've been married 25+ years, have beautiful children, the age disparity between them is now more obvious (his age is starting to show) but she appears just as devoted to him as I see in younger newlyweds.