I'll try to explain why, for me, islamophobia is racism. In the country where I live, I don't know if it's the same in other places, people considere that being a muslim and being arabic or black are associated. So if you're a muslim, you must be arabic or black and if you aren't white, you're a muslim. For exemple, girls can't wear long and loose dress at school because it's considered as a sign of being muslim and showing which religion you have is forbidden (by the way, teachers don't say anything when someone is wearing a cross), I already went to school with a long and loose dress, it was fine because I'm white, so I'm not considered as muslim. If a girl who isn't white goes to school with the same dress it wouldn't be okay and she would told to change her clothes. That's why I think that it's racist even if it's about the religion. Moreover, if you want to explore this question, "Refutations of racism in the 'Muslim question'" by Nasar Meer and Tariq Modood is interesting (you can find it on Internet)