I have my doubts about that as well. I would think that the lack of K-9 teams near departure gates is a good sign that bombings are not the concern of the TSA when it comes to airport security. Bombings are probably a concern somewhere, but the security checkpoints do not seem to do much when it comes to stopping a bomb plot.
Keep in mind that private planes are exempt from the security checks. If a terrorist wanted to blow up a commercial plane, what would stop them from chartering a private jet, bringing bombs on board, and then ramming their explosive-laden plane into an airliner mid-flight? Why even bother doing it in flight? A terrorist might just roll their chartered jet into a fully-loaded passenger plane on the runway, and blow up a plane in front of a crowd of people.
Perhaps there is some other procedure in place to ensure that no bombs can make it past the numerous ways that people and vehicles can enter an airport without going through a security checkpoint. If that is the case, what is the purpose of the checkpoint? Why not just apply whatever techniques prevent terrorists from ramming private jets into airliners to the rest of the airport, and let us keep our rights intact?
It is also worth pointing out that there are lots of other bombing targets that are not being bombed, despite a complete lack of security. Anyone can bring large packages onto the NYC subways without any harassment or scanning, yet those trains (which are packed with hundreds of people during the rush hour) have not been blown up. A truck full of explosives could easily drive onto a major bridge. Yet despite these clear vulnerabilities, and despite the fact that other countries see such attacks and more, we rarely have them here. Are airlines really more special targets for bombers than urban transit systems?