Here are some points I don't think you're getting GF:
- The people in those other killings you note were domestically or otherwise engaged with the killers
- Terrorist attacks are in fact like acts of war, they target a people a culture, they're thus different from but of course related to the cases where an individual strikes out at society in random killing.
In fact there is reason to think the terrorists are losing and badly at least vs. the US, a stupid fight for them to pick in the first place as I think the main orgs have figured out leaving only lone operators at this point. The same act perpetrated 20 or 30 years ago might have resulted in a prolonged case even with individuals at the level of competence of the Tsarnaevs.
Agree that killing is killing and both are symptoms of problems in society and maybe the domestic thing is more pressing actually because of the numbers, but there is a fundamental difference.