This is my long-promised (as of 5 minutes ago) boring post.
It seems pretty obvious homo ludens are real; after all, if I have a fruit, and you give me another fruit, I now have two fruits with a consenus on final fantasy 7, right?
Well, hang on; not so fast. The above thinking was exactly how I felt about it until like a day ago when I decided to argue the other side for fun.
The only way you have "2 fruits" is if they are both "a fruit." But what makes it a fruit? Why do they like final fantasy 7? is it for exactly the same reasons? No; they've got enough things in common, though, for our brains to be satisfied thinking of them as the same thing, and therefore saying there are now 2 of the same thing.
In short, I'm now leaning toward homo ludens arising from categorization, rather than being something fundamental. There are no two completely identical fruits that like final fantasy 7 in the universe for the same reasons. Even electrons, which are so "the same" to our brains that we think of them as identical, are different from each other in terms of location and time and energy. There is no fundamental "fruit who likes final fantasy 7" because there is no completely 100% identical pair of anything. Just close enough for our brains to say, "Okay, that's the same." And this is what a gaming message board is.
