Associating the act with the events on the day that followed is unsubstantiated.
Planting bombs at both political party headquarters sure seems like the action of someone that is disgruntled with the entire system. Perhaps someone that would go on to riot against the peaceful transfer of power within that system.
Exactly. We don't prosecute based on whims, but tangible evidence. You'd be wise to do the same.
Besides, who placed the bomb, again, does not influence the heinousness of the act. Placing pipe bombs at political party headquarters is an atrocious thing to do, and relevant agencies in DC are right to be on edge about this kind of behaviour. That is not "maximising", it is a prudent course of action.