Disgust is a primary emotion.
The others are anger, fear, happiness, sadness, surprise. There is some controversy about how to group these basic emotions, but generally, expressions associated with primary emotions are recognizable across all cultures and are experienced by all functional human beings.
A new study has found that stress, which is probably interpretable as disgust in this case, was experienced by all of the (heterosexual) men being studied when viewing male-on-male kissing.
From the study’s abstract:
The results of the current study suggest that all individuals, not just highly sexually prejudiced individuals, may experience a physiological response indicative of stress when witnessing a male same-sex couple kissing.
The study is here: What do two men kissing and a bucket of maggots have in common? Heterosexual men’s indistinguishable salivary a-amylase responses to photos of two men kissing and disgusting images.
Co-author of the study, Karen L. Blair, says:
It is difficult to specifically state what this means. It could mean that participants found the images of male same-sex couples kissing to be equally disgusting as the disgusting images. It could mean that they had an anxiety response to the male couples kissing and a disgust response to the disgusting images, but that physiologically, we could not tell the difference between these two emotions. (Straight men’s physiological stress response to seeing two men kissing is the same as seeing maggots)
Make of this data what you like.
Just two months ago another study found that disgust plays a significant role in how people respond to people from other cultures or who look different.
An article about that can be found here: Multiculturalism fails due to “behavioral immune system”.
In my view, it is hard to argue with primary emotions. Our neocortexes may want us to be perfectly tolerant and judiciously blind to all human differences, but maybe that’s not actually possible?