I would guess the order just indicates they started as a fighter, not that they are mainly a fighter. So a 1 level dip into fighter first for heavy armor and a fighting style, then melee warlock from there makes sense to me.
Otherwise, maybe it’s just people thinking that fighter 5/warlock 5 gets you just as many attacks as a full fighter, and also fireballs/hex etc
Crunching the numbers in your example, there’s a 92% chance no coin does better than 55% correct. Randomness happens, but the law of large numbers usually refers to much larger numbers than 1000, and there aren’t 1000 huge companies being investigated right now. I think suspicion is warranted here