It's an enormous issue because violent arabs will throw a tantrum if "we" say where the capital of Israel really is, so let's treat them like children, right?
If I ask where you live, and you tell me Florida, but I insist it's Ohio, who is right? Me, because I'll threaten violence, or you, because you own the house, maintain it, pay the taxes, etc?
If the USA recognizes Jerusalem as the capital and nobody other than us and Israel agree, so what? I'd like you to answer. So what?