I've come across uncut guys who have experienced negative reactions to their foreskin. One guy in particular was deeply ashamed, almost to the point of tears, when he revealed his penis to my friend for the first time. For him, he grew up in a rural area, and the stigma that haunted him was the perception of coming from a poor, backwoods culture, where only those people retained their foreskins.
For the most part, from what I have heard, people have a negative perception of foreskin due to potential hygiene issues. Like it or not, smegma is a thing that a lot of people simply would rather not deal with. From my own personal experience, all the uncut guys I have had sex with were very diligent in cleaning themselves. But, not everyone takes care of themselves. One example that I personally have was of this hot young business guy cruising me at a urinal beside me, who leaned back to show me his very thick, hung, uncut dick. Hot..but then he pulled his foreskin back a bit and it was like he never learned how to properly clean himself. It was..repulsive.
All that said, if given a choice, I prefer uncut guys. All that extra skin feels wonderful inside you. Also, for me, they are aesthetically pleasing. I think a lot of that also comes from being surrounded by cut guys all my life, so a foreskin is different, and something to be explored and enjoyed whenever I meet someone with one.