How does an 18 year old become a terror suspect...?

[nothing2lose]

Disenfranchised, disaffected young person living in the outer, lower socio-economic suburbs of Melbourne. A "Have Not". Probably underemployed, probably feels jibbed that his life isn't as good/bountiful as the ads say it should be. Feels "different" or less accepted due to religion and/or ethnicity or other demographic. Young male with brain not yet fully formed, awash with hormones, not sure how to productively deal with feelings of anger and alienation. Once upon a time would have joined a gang, hooned around the street in a stolen car, vandalised bus stops, etc....but instead found a sense of belonging with a group of like-minded thugs hiding behind religion to "legitimise" their anti-social behaviour.
No different to bikies, nationalist/racist groups, car hoons, etc, etc, etc....

I live in the outer suburbs of Melbourne. I see these disenfranchised teens all the time. They might express their disillusionment and anger in a different way but they are all the same underneath IMO.

[Lenny]

How tough it must be to spend your life subjected to abuse, sideways glances, misunderstanding, just because of what you wear, what you believe or what you look like.
Muslim, Sudanese, Aboriginal, even transgender youth to name just a few. How exhausting and demoralising to know that so many people have you summed up before you even open your mouth. Enough to make you want to give up before you even try. For some, their parents have probably been through the same, or even some worse form of hell. No wonder you want to stick together with those who understand what it's like. No wonder you are angry and feel shut out, different, unwanted, misunderstood. Paradise lost.

[onthefly]

Remove the terror label, and I would have assumed disaffected youth with mental health issues. The other stuff may or may not be relevant.
I would say probably the greatest terror threat suffered by Australians day to day is domestic violence.

[nothing2lose]

Same same but different...

Robina shopping mall 'gunman' meant to kill: court