"This thing" referring to any element of a person’s psychology. I’ve seen these kinds of posts referring to bisexuality, genderqueer, transexuality, anxiety disorders, eating disorders, body dysmorphia, depression, and Asperger’s syndrome, to name a few. To anyone who writes such posts: since when did you become an expert on what’s going on in other people’s heads?
Do these people not realize how unfair the situation is that they’re putting someone in? There’s almost no way that someone can satisfactorily prove to you that whatever you’re accusing them of fabricating does indeed exist in their psyche, just as there’s no way you can satisfactorily prove to them that any element of your psyche does indeed exist. If they demanded that you prove that you don’t have that element of their psyche that you are claiming doesn’t exist, could you do it? Probably not, so it’s unfair to expect them to do the same.
Yes, for some of these things, there are scientific studies backing up their existence, but it’s a pretty shitty move on your part to demand that a person use science to validate themselves in your eyes when they don’t expect the same of you. Show your fellow humanity some goddamn compassion and show the same faith in their honesty that they show in yours; is that so much to ask?