Some evidence that was against him:

    claimed he was going to acquire molotov cocktails, pipe bombs, guns for re enact columbine
    said he was going to blow brains out of skulls
    had bomb making documents on his PC
    had folders on his PC of high profile serial killers
    watched videos on how to make a sawed off shotgun and molotov cocktails
    ex girlfriend testified he had drawn out plans on how he would carry out an attack on his high school
    ex girlfriend testified he was obsessed with one of the students who carried out columbine attacks

IMO guy was far from being just edgy. Dude basically set off every red flag indicating he was an actual threat and not just a troll.