I believe that Shinn (although I hate Shinn to some extent) does think sometimes. Like when Shinn decided to take Stellar back to Neo. He hacked the specs for Stellar's Gaia and got the code so that he could give her back. Now that took some thinking. Now how he abducted her and the fact that he held Neo to that promise was stupid. So all in all Shinn does think a little.

Now Stellar's death is in fact a group of peoples' fault.
First Neo. It is his fault for putting stellar in in the Destroy in the first place and telling her about scary things.
Next Sting. It is his fault for going down like a bitch and losing to three Orb suits while he was piloting a gundam with funnels. That was the most pathetic death in this series so far.
Now the Archangel. It's their fault for bringing Kira.
Now the Minerva. It's their fault for bringing the emotional Shinn.
Now Shinn. It's his fault for rushing in like some kind of wannabe Kira with a heroic attitude, cutting open the destroy's cockpit, and scaring the hell out of Stellar thus making the situation 1000 times worse than when it was when it was just Kira and the Archangel fighting because she became even more parinoid.
Finally Kira. It's his fault for just being there. He decided to shoot down Neo which nearly broke Stellar. He also didn't have to stab the positron cannon. He could have kicked Shinn out of the way dodged the blast and finally cut off one or both of Destroy's legs and letting it fall backwards as it fired its positron cannons. Then Kira could have slowly or quickly disabled all of the weapons that the Destroy had, or let Stllar completely lose it, shoot something and have some gun backfire resulting in Stellar killing herself.
I almost forgot Stellar. Its her fault for looking at the freedom instead of Shinn. If she really trusted Shinn with protecting her she would've stayed calm and NOT remembered what Kira did to Neo.

Destroy gundam wasn't right for Stellar anyways. Her attenion span and skill aren't large enough to fight with that suit. I believe that destroy was wasted on Stellar.