It fit perfectly.
He wasn't a military man. He wasn't on a military vessel. He had no military training. He was just a pissed-off miner who's had over twenty-five years to stew. To him it was more of a casual phone call than an attempt to open talks with an enemy vessel... and that's exactly how it came across.
YES, and more: As a Romulan, he might be significantly older than Pike or any other human he would come across, for that matter. And, as you mentioned, he had 25 years
to sit and wait. I'm a bit concerned about what he was doing in that time (like, does it have anything to do with why the Klingons have "warbirds") but I'll bet a good part of it was spent researching the command crew of the NCC-1701 - maybe,
although not necessarily for the validity of what I'm putting forward, even including holodeck time. He spoke to Pike like that because he felt like he knew him.