Frank's suggestion is good, file an ASRS and try to get any recordings from the airport. N238JP may likely have a cockpit recorder.

Did N238JP taxi onto the runway or simply make a call?
Looks like in the video he is still on the taxiway.

Did you see the TWO powered aircraft at the other end of the runway?
If you saw them, why did YOU decide to use RWY10 when two other pilots were planning to use RWY28?

If the FAA interviews the Unicom operator and the pilot of N8217G in position behind N238JP, will they say they heard your call or support N238JP?

The Citation pilot did not sound "snotty" to me, but rather reacted as many pilots might react. Since N238JP was on IFR flight plan, he may well have been getting an IFR release from ATC when you made your call.

As you indicate, you were working your camera prior to takeoff, so you have no evidence of making the call. Working your camera between making your call and the takeoff does not look good for your side, nor do the conversations with your passenger. Both items indicate a lack of a sterile cockpit.

Which runway did N441CC use 15 minutes before and N7999K use 15 minutes later?
Taking off opposite direction to other traffic and having a lack of respect for other aircraft and pilots, can give those of us in the soaring community a bad reputation.