Take a short look on piloswine's rating and compare it to magneton's. Yes, it is ridiculous.
The person at GamePress who has casted the dices for pokemon rating must have been unlucky here.
If you do not aim for Dragonite but for Gyarados, compare magneton's rating with Lanturn's. Yes, it is (even a bit more) ridiculous.
I have not found an explaination for the rating table. My working hypothesis: Numbers from 0 to 10 are given according to CP and, if a pokemon is on attacker's or defender's tier list, adjusted manually.
If this hypothesis is true, rating is nonsense, sometimes misleading.
Actual Tier lists, actual moveset evaluations and Stat-distribution are sufficient.