Neurologically, you aren't really wired to find babies cute until you interact with babies. During and right after pregnancy, there's a mental switch that flips that tells you "This is my baby; I should take care of them". People who aren't moms, but who interact with babies, also start to gradually like babies more. It's natural--we're wired to protect and raise the next generation. True of guys as well as girls, because humans in general have a pair-bonding/group social structure.
I'm willing to bet that if you guys who say you don't find babies cute were given a baby to take care of that you couldn't find someone else to baby-sit, you would still take care of said baby, and eventually start to find the baby appealing. I don't know whether you would find the baby cute, per se, but you would start to bond with it. Finding the baby cute isn't nearly as important as having the desire to protect the baby. You can look at a baby, see a wrinkled little ratlike creature, and still care about its well-being.