Personally I think he was hoping the raid would spread into something more.
After all the Hutaree bunch wanted to go running to the Michigan Militia property with the FBI hot on their tails. Seems like a great way of handing access to the FBI.
Also there was apparently a lot of chatter on the net calling for militia reinforcement. It makes me wonder if the FBI and pals weren’t trying to draw others into the trap.
Most plausible theory I've yet to read.