The fact that these guys are Islamic Extremists sheds any notion this is a false flag. If false flag, the brothers would be skinhead Nazi types.
If this was a false flag to take our guns, these two suicidal gents would have just started shooting at the crowd with legally purchased and registered guns. The bombs are already illegal.
Unfortunately this is a case of two Chechen Islamic refugees coming to America and trying to be Islamic while living in Boston. Obviously that did not work too well.