That's just because you are a woman who was brought up to find men attractive.
It didn't stick, but you remember the indoctrination.
Men on the other hand, who are still straight, somehow, do not see beauty in other men.
(I'm sure I used this quote recently)
Daryl Mitchell's character said this when he was on the John Laroquette show on the topic of sharing a bed with John Laroquette... "I have three rules! I do not sleep with men! I do not sleep with white men! And I do not sleep with ugly white men!"
To a straight man, from the 20th century, watching Voyager, Tuvix is no more attractive or unattractive than anyother man on that ship.