Why is it bad to be Islamaphobic (afraid of Islam)?
There are people who claim to be “religious Muslims” and want “separation of mosque and state”. If true, no reason to fear them.
But Islamic Muslims, by definition, want to bring sharia law and spread Islam. Looking at 1000+ years of history, including recent/current events, the only rational action for non-Islams is to fear Islam.
Phobia is a fear of something as you stated. I’m not afraid of Islam. I hate it, with bold courage.