No one would be a sewage worker if this was the case.

I see that this opinion is referring to moral right or wrong, but to advocate for an alternative explanation: if we don't assume that this opinion concerns morality, I thought it might be interesting to mention that there are evolutionary explanations to disgust. We evolved to feel disgusted by certain materials and phenomena as a protective mechanism against disease vectors. If something is disgusting, it just might be the 'wrong' thing to do with regards to one's personal health. Returning to morality, however, our capacity to feel disgust has been tapped into by societally and culturally motivated stimuli. Disgust can certainly provide an indication of whether something appeals to one's internalised sense of right and wrong. Whether it is, can be, or should be relied upon in all scenarios is another question. TheMastaDebata gives a good example of where it cannot, as we do indeed refrain from judging sewage work to be 'wrong' despite a virtually universal disgust for it. The infidelity of a romantic partner in an exclusive relationship can also elicit disgust, and is often judged as a wrongful deed. We make our judgements based on numerous factors and, while disgust does not play a singular role, it, it can certainly contribute. - IN BRIEF: we use disgust as a sociocultural cue as well as an evolutionary mechanism. Though we do not make our final judgements solely upon disgust, it cannot be ruled out as a factor that 'helps you judge […]'.