That's an incredibly long time to lay on the horn at someone. If you count 8 seconds in your head you'll know what I mean.
The guy shouldn't have followed you -- that's stupid and you were smart for going to the police station. But c'mon -- honking at him at 6 lights with the final one being a long ass blast? You were no angel in this story. Either realize he's just the type of driver who doesn't move right away or pass him, or find another route home. Don't be a dick with your horn.
EDIT -- I also have to assume this is an overly nice version of events from your perspective. I have to assume the honking was more aggressive and probably less warranted than you are suggesting.