Well, a couple things.
First, it's not hard to judge the distance of a vehicle behind you if they are there long enough. I usually use some kind of mark. When the rear of my car passes it, I start counting. If they pass the mark before I hit 2-1000, they are too close. Not the most totally accurate measuring tool, but if they pass before I get to 1-1000, they usually get a flash of light. Only a very few ever get stopped.
I get the pulling over to the left thing, as I have written tons of those tickets. Here in NM, people have a tendencty to see emergency lights behind them and stop in the lane, or move to the left where we are trying to pass. That ticket is also written sparingly.
I'm with others who have talked about him driving under the speed limit in the left lane. Here in NM it is a citable offense. Drivers are only supposed to be in the left lane to pass. We get tons of "left lane vigilantes" who get tickets all the time for refusing to move over.
Only you were there, but if you weren't riding his ass, he may have a hard time convicting you in court. He will testify that he was traveling at whatever speed in the left lane. You need to come back by gettin him to admit he was traveling slower than then posted 65. If he does that, then ask him if it is illegal to pass on the right. Ask him if it is illegal to drive and block the left lane. When he says it is (the judge knows the answers to these questions) make him tell you how you could have gotten out of that situation without a citation.
He sounds like maybe he was having a shitty day, or maybe he's just an arse...You never know, but there's always one.
However, next time, move to the right...It really does irritate us when people move to the left. It messes with out plan, and people end up getting hurt by passing cars.