At the end of the day, the man just appears to be a crazy person with delusions that frequently bleed into him acting in real life. Whether what he sent out could have detonated may not be overly material. His intent was probably to kill. However, he doesn’t appear to be particularly bright.
Of course the possibility that he wanted to be caught can’t be ruled out. Perhaps the bombs weren’t intended to kill, but to simply lead back to him and get some attention/fame. He’s obviously been arrested enough times that I doubt “I could go to jail” has much power over him. Maybe he even likes living in prison more than the outside world. I’ve heard of people who felt that way(especially the mentally ill).
I see no evidence to suggest he’s working on behalf of Democrats. He strikes me as a fairly typical Zerohedge poster(except he actually acts on his delusions).