This is also pretty interesting question for me, as I woud love to know some way to identify abnormal people like myself who otherwise hide very well. But did not managed to meet or identify anyone anyone so far.

I think in my case almost nothing suggests that i like guro besides maybe the fact that I am not nonjudgmental in any way so there is no way anyone would creep me out.
If someone confessed to me that she ate her baby I woud just ask how does it taste. and even if someone say something negative about me, my response is "Hmm how interesting why do you think so?" but of course that does not count for situations when those people can do some real harm to me.


Otherwise nothing special. maybe I count as schizoid personality to some extent (but not a disorder just personality ) I guess it is very likely that other schizoid/introverted and also some autistic people will have some similar interests as well. but unfortunately those people rarely go to public so you will not meet them. Probably that loner factor also counts as signal that person may be into guro.

From my little experience and from wast other people say I decided that you should always take jokes seriously. This is the time when people say actual truth. so jokes and reaction to jokes can be the real red flag which can reveal most of the stuff about someones personality.
also you have just listen to what they say and take every quirk seriously especially if it stands out somehow.

Here is one example situation which happened for me as one girls decided to mock me and ironically said that she has very black soul(I wonder if she is not here?) what she later immediately denied and said that it was just a reference to some advertisement song. but later I interrogated her and even if she said that I am disgusting for what i say, she admitted to fantasize about being a boy, she was goth who has no friends and no boyfriend wast finally ended with her admitting that she is delusional and lives in her fantasy. What kinda suggests schizoid personality it woud be pretty nice to have her as girlfriend ;)

Another story from YouTube about one guy who gad a girlfriend who admitted that she sometimes to kill "The Sims" characterless by letting them starve to death.