Once the book is being sold to B&N, etc., we can't leave out the genre info. In fact, before we buy the book, we have to decide what the genre is, because we need to put it on the schedule, and our schedule gets sorted by SF, Fantasy, Mystery, Romance, etc.
There are three questions you need answers to:
1. Did you really write a hard SF novel?
2. Who are the people telling you that it is romantic? Are they romance readers, or SF readers? Do you know any hard SF readers who are willing to read your book and tell you what they think?
3. Do you care? If you send your hard SF novel to an editor who wants to shelve it in romance, and everyone who reads it thinks it's a romance, and the editor is convinced it will do well as a romance... do you *really* care that it is not shelved in the SF section?
Re: confusing
There are three questions you need answers to:
1. Did you really write a hard SF novel?
2. Who are the people telling you that it is romantic? Are they romance readers, or SF readers? Do you know any hard SF readers who are willing to read your book and tell you what they think?
3. Do you care? If you send your hard SF novel to an editor who wants to shelve it in romance, and everyone who reads it thinks it's a romance, and the editor is convinced it will do well as a romance... do you *really* care that it is not shelved in the SF section?