Okay now for some input.
I am a Muslim myself, living in the west. I did want to hear some of your answers.
Time for some clarification.
First of all, I want to dispel the myth that there are actual recruiting centers. It appears that mosques work close with the government and every mosque I have been to has these "Anti - radicalization programs" to convince Muslims not to join the conflict.
I know some people who have left to fight in Syria. When I asked why, they said it was to help the Muslims in trouble there, because according to Islam, each Muslim is part of a single body, and if one body part is injured, the system feels it as a whole.
Some of those fighters go there for what they claim to be humanitarian reasons. They claim that if their host countries don't want to oust the Assad regime, then they will take up arms and do it with someone who will.
For those Muslims who go for humanitarian reasons, is there anything that a Muslim can do in a liberal democratic country that will help those living in Syria without having to resort to fighting?
I know ISIS is mainly concerned with establishing an Islamic Caliphate. There is some appeal of that from educated Muslims, who tend to think globally and want a tight union between all other Muslims, but a lot of those people also go with the intention of serving the people in trouble there by ensuring that donations reach their intended destination (and not confiscated by the Assad regime) and defending those unable to defend themselves.