Because circumcision is performed on the sexual organ it is intertwined with sexuality even though many people don't really regard it as something obviously connected (e.g. because they think of circumcision as a religious obligation not to be discussed in the context of sexuality).
In some cultures removing one's foreskin is part of the initiation process into adulthood and one is only allowed to have sex once his foreskin has ben removed, in which case the connection between circumcision and sexuality is quite direct.
I can't even claim that the idea is lost on me. My foreskin was removed in a sufficiently painful manner, in my teens. At that time it really did feel as a sort of threshold one has to cross from childhood to adulthood.
On the other hand a lot of people are circumcised simply for health or religious reasons often at an age before sexual maturity in which case conceptually there may not be any connection between circumcision and sexuality, but in reality they are always intertwined in some way.
Perception of one's own body image and sexual attractiveness can also have an impact (be it negative or positive) on one's sexuality.
Interestingly one major psychological / cultural effect is that circumcision de-sexualizes being naked with one's glans showing. Some cultures, especially the Graeco-Roman antiquity in Europe did not think of nakedness as indecent, but showing one's glans in front of others was a completely different matter. Till this day a lot of people still feel that way, and consider a retracted foreskin even e.g. in a public shower (where certainly there is a good reason for it), or really anywhere except in the bedroom getting ready to have sex, embarrassing, or indecent.
While many cultures that practice circumcision do not condone public nakedness in some others nakedness is common in some social situations. In North America, for instance, guys walk in front of each other naked in locker rooms and showers without giving it a second though. Obviously if most guys are circumcised and walk around with their glans showing it is no longer considered to be sexually explicit, just part of casual nakedness.
In non-circumcising parts of Europe till this day many people tend to think of the bare glans as something inappropriate to show (and discuss the topic ad nauseam on the Internet for some unfathomable reason). I remember growing up, while casual nakedness was acceptable in various situations, nobody has ever walked around with an exposed glans. Even guys with a naturally short foreskin kept adjusting it so it would not slip back and leave the glans completely uncovered. Like everyone else I would not show my dick with my foreskin retracted in front of others as many would have viewed it as inappropriate.
After my circumcision the awkwardness of being seen with an exposed glans has gone. Since my glans is always bare, not having it covered in skin does not feel sexual or indecent in any way. Not sure if everyone's brain makes this switch as some people who are opposed to circumcision seem to list embarrassment when others see their naked glans among their complaints why they don't like being cut.
On the other hand it looks like that over the last few decades walking around with one's foreskin retracted 24/7, including in public showers, locker rooms, and nude beaches has been becoming increasingly fashionable in some parts of Europe, so attitudes are changing albeit slowly.
Even though circumcision makes the bare glans casual the situation is not that simple. Many people profess having some sort of fetish related to circumcision -- getting sexually excited by either the act of cutting off the foreskin, or by the circumcised penis. Intactivists often claim that any preference for being circumcised or for circumcised partners must be a fetish, conversely in communities that practice routine circumcision often the refusal to get circumcised is viewed as a deviant behavior and preference for the uncut member is ridiculed as "foreskin fetish".
I don't think a simple preference for a circumcised penis -- be it one's own or a partner's -- constitutes any sort of fetish. For that matter neither does the preference for a penis with a foreskin. Normally fetish is understood as sexual arousal tied to something other than genitalia (other body parts, or even inanimate objects), so preferring one type of genitals over another is not a fetish.
On the other hand having sexually charged fantasies about being circumcised in some sort of forced and restrained manner can be considered a kink. I am not exactly sure why people find that arousing (my imagination regarding BDSM is probably very poor). Being circumcised without anesthetic is just too painful to be pleasurable (sexually or otherwise) while if you get it done under anesthesia you are not going to feel much, which isn't overly exciting. Nevertheless some people use real circumcision paraphernalia (such as real circumcision clamps) as sex toys of some sort, occasionally tightening them for real and risking permanent damage to their foreskin.
Unfortunately for many people involuntary, often painful circumcision, often under restraint is exactly what happened to them in real life, and they may find it one of the most terrifying experiences they have ever had to go through. Surprisingly the two groups (the ones who find it arousing and the ones who had a terrifying experience) may overlap -- the human psyche works in mysterious ways and "a compulsion to reenact a traumatic event" is a real thing in psychology.
On the other end of the spectrum sexual arousal tied to dealing with rotting smegma, or glorifying phimosis is most definitely a kink.
Being circumcised, and feeling good about it is not a sexual kink. Quite the opposite, being a circumcised guy among circumcised peers allows a higher level of nakedness to be treated as an entirely casual non-sexual situation, promoting a positive body image instead of treating some parts of the male anatomy as some sort of taboo that others must never see.
