I've thought about this, and when you break it down, episodes 3-8 are really just the Defenders trying to come up with ways to fight the Hand and then settling on killing them all with dynamite. Which they don't come up with - Colleen does. It's a plan that works, but it shouldn't have taken them that long to think up.

"Where's the Hand?"
"I don't know, but we just fought them in that giant new building they own that's over a secret cave so maybe they're there?"
"Good idea let's go fight them but not bring any weapons of significance."


Nuke them from orbit. It's the only way to be sure.