* The phrase “Is that even a thing?” has a specific usage. I first encountered the phrase when listening to my then college-age daughter, and was quite struck by it. The intended meaning of “thing” in this phrase is something like
“An activity that a substantial number of people do.”
For example, take “whale-watching”. This does not mean “I happened to see a whale.” “Whale-watching” means that I bought stuff to do it with, I paid for tickets to do it, I rode with a number of other people on a specially-designed boat on a voyage the specific purpose of which was finding, getting close to and yes, watching whales.
The phrase “Is that even a thing?” expresses something more, namely, incredulity or at least doubt, that something is an activity that a number of people do. If you asked “Is whale-watching even a thing?” you are expressing at least doubt that people really engage in whale-watching as an organized activity. (Well, I’ve done this myself, and I can assure you that whale-watching is, indeed, a thing.)
However, when a native speaker (I’d say a millennial) uses this phrase, they are sometimes doing more than simply expressing doubt that the named activity is actually recognized as an activity, and is done by a substantial number of people.
They are trying to control what is a thing, in the sense of the last sentence of your post. They are seeking to have deep power over the thoughts and activities of their social group.
