If you come at me and tell me that Islamophobia isn't racism because it's a belief system, or that the reason Islamophobia is acceptable is because Islam in itself makes it so that its adherents are deserving of discrimination, I'd like to remind you that no matter what I did, I'd still be subject to Islamophobia.
That means that I'd be subject to increased risks of assault.
I'd be profiled on the borders of Western countries.
I'd be asked to justify the crimes of my co-religionists.
Even if they aren't my co-religionists.
It doesn't matter if I'm a Muslim, no matter what denomination, sect or religious movement. It doesn't matter if I leave the religion. It doesn't matter if my orientation or gender identity makes it that other Muslims want me dead. It doesn't matter if I criticize Muslim authority, or become a staunch opponent of “radical Islam”, or just plain old “Islam”, or if I want to “reform” it, or gut it in half, or ban it. It doesn't matter if I become a staunch proponent of white supremacy. It doesn't matter if I change my name into something more “neutral”, or try to hide my heritage.
Just one word — “taqiyya” — discredits all of that, because Muslims (actually Shi'a Muslims, who used it to stay safe from Sunni violence, which is another fount of fuckery I won't cover just yet) all lie to save their skins and spread shari'a.
Hell, it doesn't matter even if I never was a Muslim — I've seen Sikh people, Desi people of all beliefs, Arabs of all beliefs, brown people, black people, all subject to Islamophobia, because they looked “Muslim”.
The crux of the matter is you're not attacking a belief system, because Muslims, and, when you get down to it, people who don't look like you, are so diverse, it's hard to figure out who's Muslim or not. So you come down on the people who look like Muslims, even if they're not. And you don't care that these people change their minds. You never have. You just want them gone.