It's cheaper for Honda to build cars in the same market that they sell them in. Import fees, currency fluctuation, and shipping costs add to this. The earthquake did significant damage to the R&D center there. I went 1.5 years after the quake, and there was still cracks in walls and reconstruction going on. Honda's ECU supplier got wiped off the map. This hampered production for like 6 months. No car factories were damaged.
Honda almost tied the all time sales record from 2007 this past year. Americans are hardly sick of them. Honda doesn't make much that is appealing to a tiny minority. Hopefully this changes with the next Civic.