Morgan I see what you're saying, I understand. I am not one to say what Belgium's rules should or shouldn't be because it is not my country, I never plan on going there for any reason as I am grateful with where I live right now. But I will say a few things to help clear up some misconceptions here.
Hijab (headscarf), as described by Islam, is a practice, not a mere symbol. It is a piece of cloth.
Islam itself is not fanatic. Fanasticism is against Islam. Sure there are a handful of Muslim fanatics here and there but why should that be used to label Islam as "fanatic?" Those "Muslims" in Belgium who don't learn the language or educate their daughters clearly have a major issue because education is a big thing in Islam, every single person on earth who claims to be a Muslim should have a drive for education. It is for cultural purposes that they do not want to learn the language, not religious. There is a huge difference. They feel that their identity is being threatened. With religion, your identity is not threatened by education, in fact, Muslims are commanded by God in the Quran to strive for education and you become a better Muslim the more you are educated.
I do see something similar to what you're talking about here all the time when from people of all cultures immigrating to the US as well. They don't educate themselves on language/culture because they're afraid of losing their culture and identity. It seldom has to do with religion. Mind you, I'm speaking from experience of someone who has grown up in one of the most culturally diverse cities in the world with high levels of immigration.
I hope you understand the differences between the cultures of some people and Islam.