You can love running, have a facebook account saying you love pokemon, video games, soccer, american soaps and sci fi movies... and still want to kill white people you despise because they ridicule you for being a skinny small frustrated muslim looking dude on a daily basis. You dont know what goes thru people s minds, their motives. Fact is anyone could build one of these bombs. There are a lot of immigrants living in the west who hate the west and white people.
Btw if these two arab looking guys arent responsible, they should have already been found and freed after investigation ? Where are they? Why would they be hiding? So many things we dont know, still most of the time the most basic explanation is the right one, even if we would prefer something more complicated, less dumb.