The offered options are neither mutually exclusive, nor collectively exhaustive. Even more importantly, there is no reason whatsoever that attitudes would spring from a single source, and they don't. Someone had a relative robbed by an immigrant, someone else is a member of a right-wing subculture, someone else directly competes with immigrants for jobs, someone else just doesn't what Rotherham to repeat, someone else believes that assimilation is integral to a functioning society and is concerned with ghettoization and radicalism, someone else just doesn't like the bastards. In some sense, a combination of "facts", "theory" and "values" will always be at play, but that's just the case for any value judgement at all, as we know after Kant. One could probably measure the prevalence of each particular source, to see if at a particular point in time among a particular group the attitude seems to be more visceral or more theoretical, but that wouldn't really tell us anything about anti-immigrant attitudes in general.