Probably correct on all counts, but by filing a complaint with both the police and the FAA it may move things enough in the right direction to prevent this captain from doing that again. You do have to ask your question what you hope to get out of it? The issue you will likely have even with filing a police report is jurisdiction.

There are a lot of circumstances against you, but to file a complaint with the authorities costs nothing. It may also be worth an email to the ACLU.

I don't get the impression the OP is claiming irreparable harm here. The issue is being able to refuse ridiculous 'orders' from a captain without being removed from a flight and making sure the captain doesn't use any measure of force like this again.

Sadly, I do think the outcome would be quite different if this happened in IAD or ORD and you had requested the police immediately with all the witnesses present. Also, if you had been removed from the flight or chosen to get off the flight instead of change then you would likely have had economic damages to pursue legally.

My attorney can accomplish a lot with a letter in most situations. Good ones can! Before doing anything or spending another cent I would advise you figure out what you hope to gain. Lawyers and fun usually don't exist in the same situation.