I don't mean to pick on you in particular, but your comment is an example of a pattern I've noticed over the last few years that results in confusion more than clarity -- using the term 'racism' outside of the context of 'race'.
In most cases, I think 'prejudiced' or 'bigoted' is probably a more accurate label when you are talking about irrationally negative attitudes towards religious, political, cultural or national groups.
Not all negative attitudes are necessarily prejudiced or bigoted. Religion and politics exist in the realm of ideas -- one person's 'bigotry' can be another person's rationality and of course reasonable people can agree to disagree without there being any prejudice or bigotry involved.
I think most of the anti-Muslim rhetoric in the US these days fits into the same bucket. I don't believe most of it is really religious. You've got Donald Trump claiming he loves Israel and Jews and then claiming that Muslims are ruining/attacking America. That's not a case where the issue is religious disagreement or Jews would be as much a target as Muslims.
Again, you could certainly call this xenophobia. I think racism is still pretty accurate, though.
I wonder what this study would find if it expanded the "racist term" set. Maybe Texans are very racist against Mexicans. Maybe Washingtonians are especially racist against Asians. [2]
[1] It's not hard to overlook racism directed at a tiny fraction of the population because you just don't see it much. I didn't think there were really people in the US racist against Jews until I was an adult and encountered people who grew up around sizeable Jewish populations.
[2] I'm not asserting either of these as fact.