The power trip and inconsistent of FA happens on any airlines as we are discussing human personalities not a corporate culture or brand. I don't think your status or approaching million miles is as much of a factor as this person had a bully power trip and didn't want someone talking back to them.
I've seen identical situations to this and in their defense (not that this scenario requires any explanation as FA is wrong) - there are passengers who think they can put their laptop bag & hat in overhead so they have open/clear foot space in front of them. In that situations the FA is correct. Unfortunately, in your situation the FA didn't realize you were bulk or exit and should not have assumed plus realize you did put your smaller item in front of you and met safety procedures. I've had this identical happen to me (backpack while seated in bulk) and FA took it out and moved it after pushing in roller thinking I was in the wrong. The FA did bring to me my backpack immediately after take-off if I needed access which calm my nerves as I'd rather have it overhead in view as I was the 10th passenger boarding the aircraft.

I hope time will calm you down and you know the CCare will result in nothing besides them restating policy which didn't apply to your situation, as you were 100% correct. Maybe, if deja vu and the rest of us quickly status, I'm in bulk/exit and already have a smaller item in front of me.
As a follow-up - I do think it is acceptable/proper for the FA to move overhead items around to accommodate a bag or efficient alignment. Just be courteous when doing it, "Sir, would you mind if I moved your item two rows ahead to accommodate this larger bag?"