Why Sci-Fi tragicomedy with a love story is not classified as Romance genre?

The Sci-Fi romantic tragicomedy "You are the Universe" is named in the official trailer as "The story of the last love in the Universe" (either believe me or find someone else who can read and understand Ukrainian).

I supposed it to have a genre mark "Romance" at IMDB.

It does not. I've got surprised and tried to request adding that to the title. My request was declined.

Could anyone explain me what is wrong there, why love story can be considered as non-romantic? I really might miss something.