Is it wrong to treat opposition to Israel's policy as antisemitic?

At times, I've noticed a seeming package-deal in the media, whereby any criticism of Israel's policies is dismissed as a form of antisemitism. Yet I've met people over the years who don't support Israel' s political positions, but they claim to not be antisemitic and have nothing against Jews. In contrast, a person against America's policies is not assumed to be anti-American. So is criticism of Israel antisemitic? Or is equating them a dangerous package deal?