He doesn't. Opinion based 100% but that's unimportant. All this is based off of is how many bitch and what your final score is. Meaning that if you bait your team and killwhore you will get near the top in no time. While the top10 might be relatively accurate the 86-82 ratings are a complete clusterfuck of innacuracy. Many that outperform others in matches being rated lower because they dont whore around for Dismounted Kills.
It seems you are a bit salty about not being rated as high as you rate yourself
Ciiges has mentioned before that this list is based on performances and alot of feedback from top players. This can most likely be confirmed by the people who have given their input.
I've come across your type alot in Native, PW, mercs and other mods I've played on. The cocky type who rates himself way higher than he actually is. Your type is usually the type to go for kills only to try and boosts others' opinion of you, sad really. This is a teambased game in any aspect besides duelling, hence why most lists are based on more than score, or opinions of lone players.
At the end of the day your opinion on urself doesn't really matter, but please do go ahead and make urself look like a fool with a big ego.