It can include romance but doesn't have to. And if the story includes a love affair, the main plot of the book can be about something else.
I see 'Romance' as a genre with a capital R coming under the wider category of women's fiction. I'm sure, though, there must be exceptions. If you've got romances like Jane Eyre under general or classic fiction you've got classification anomalies and confusion can set in.
So, yes, generally better to think of it all as contemporary fiction or, in the case of Jane Eyre, not-contemporary fiction.
Rick rightly mentions marketing. Cover designers need to know the market the book is aimed at. If we got rid of categories would cover design, for example, do categorisation in some kind of better way? I don't know, and I'm getting far out of my knowledge zone here 🙂