I think it's common for people to talk about kink as if it's a spectrum. You're more kinky or less kinky than any given person. I don't think this is quite accurate though. It's not always wrong to talk about kink in these terms. Some people are certainly more kinky than others and it can be an easy shorthand in casual conversations but it doesn't really capture the complexity of kink or the individuals whom enjoy it.
To say that kink is a spectrum is to say that any given desire, activity, or interest falls somewhere on that spectrum. It implies that anything can be classified as more or less kinky than anything else and that a person at a given point on the spectrum will enjoy everything behind them on that spectrum. This simply isn't true.
Kink is an a la carte endeavor. You don't select a spot on a spectrum. You pick and choose what you enjoy from a massive list. It's a beautiful thing and it produces interesting an unique individual preferences. There are people into serious masochism and degradation but who are uncomfortable with any sort of public displays of affection. There are people who enjoy being treated like pets but find the idea of being treated like a baby to be degrading (in a bad way). These individuals don't occupy a spot on a line. You can't say they are more or less kinky than someone else based on any individual desire or limit. They are unique.
I suspect the discussion of kink as a spectrum is rooted in the natural inclination of people to classify themselves as normal and anything outside their preferences as deviant in one way or another. George Carlin used to do a bit about how, when you're driving on the highway, anyone driving slower than you is "an asshole" and anyone driving faster than you is "a maniac!" We all have a tendency to think like this and it can affect our views of so many things. It's easy to say anyone who doesn't enjoy my kinks is "vanilla" and anyone who enjoys kinks I don't is "really kinky." It's an inclination that, in kink and so many areas of life, tends to inhibit empathy and understanding. It's an inclination that is worth fighting against.
I think the danger of describing kink as a spectrum is that it can confuse newcomers and place pressure on people to do things that they simply don't enjoy. I've known people whom enjoy some fairly kinky activities and have seemed to feel embarrassment or guilt that they didn't enjoy something generally considered less kinky. "I enjoy being spit on, I shouldn't have a problem being called degrading names." "I like being slapped in the face, why don't I like spankings?" Just as it's sad when a person feels shame for the kinks they enjoy, it's sad when a person feels shame for the kinks they don't.
Again, this isn't to say that the idea of a kink-spectrum is never useful or that you can never say one person is more or less kinky than another. It's fair to say that a person who enjoys bondage and corporal punishment is more kinky than someone whom prefers missionary-position sex with the lights off and no talking (not that there's anything wrong with that, if that's what a person is into). Still, for those of who are into kink, I would argue that it's generally not helpful to talk about it as a spectrum. It oversimplifies a complex set of interests, confuses newcomers, and puts undue pressure on individuals to like activities that they simply don't.
