I believe the original quote to that effect was by Robert Hare and the basic premise of it is that if any part of you worries you might be psychopathic, you're probably not psychopathic enough to worry about it. The worryingly psychopathic don't see psychopathy as something to worry about.
Everyone places somewhere on the spectrum, the question is only where.
One of the defining characteristics of being a psychopath is an inability to feel shame or empathy. If you feel bad about being a psychopath, then a.) you care what some online test thinks about you and b.) you are capable of feeling shame, thus by definition you are not a psychopath.
The one exception is if that test or diagnosis makes it impossible for you to achieve your goals. For example, if somebody broadcasts to the world that you're a psychopath and that means you get turned down from jobs or the government starts a manhunt for you, then a psychopath would feel bad. But on a self-report questionnaire on the Internet? That has no consequence on your actual life? If you feel bad about your psychopathy score there, you're almost certainly not a psychopath.
Psychopaths are notoriously difficult to treat. Most of the reason for this is that, by and large, they simply don't want to be cured. This isn't to say that they're enthusiastic about being psychopaths, but they don't see it as being problematic enough to be worth the trouble of changing. In other words, while they may not necessarily want to be psychopaths, they don't particularly want to be not-psychopaths either.
If you're actually worried about being a psychopath, then clearly you want very badly to be a not-psychopath. If it's that important to you, then you're missing one of the critical markers of psychopathy.
