Some authors say they don’t have time to read. That’s like a starving castaway saying he has no time to eat. You’re not that confused, are you?
But maybe you have a similar problem: You have no relationships with books outside your niche. For example, your write youth fantasy and read only youth fantasy. Why is this wrong? There’s a nasty word for families that have relationships only with themselves. Authors who only read their genre may fall into that same category.