I'm looking at Tom's matchup chart, and tbh, there's not really a good argument as to why she shouldn't be where she is, which is a very solid 9th place.
It can be irrelevant at the highest levels, but the reality is that Sonya is a character who doesn't really have good ways to deal with zoning. She has mostly what everyone else has: dash and block. Her arch kick can be used (Although I highly doubt a lot of people are doing this on reaction) and EX cartwheel. Now even compared to Johnny Cage and Jax, characters who are known to have a similar overwhelming offense, this does not really take care of projectiles quite as well since it only covers less than a quarter screen (It makes up for that by being a better reversal than EX Shadow Kick or Dash Punch respectively, however).
I would argue that she is slightly better at dealing with projectiles than Johnny Cage, but only barely. Johnny Cage can be zoned out incredibly easy, and if you think about it, Sonya can as well. She has very few answers to IaGB stuff, and up close it's still a matter of picking your armored spot in a particularly strong offense. It's probably not the borderline 7-3 Tom has it, but clearly there are very few spots where Sonya has the advantage.
Moving down, she clearly loses to Kenshi, no doubt. Freddy is arguably a little more fair, although I still can't rightly say it's in Sonya's favor. Freddy, as I believe has been mentioned above, has really good corner escape tactics that is normally the issue with most zoning characters. Smoke is another character who can run from Sonya once he takes a life lead and doesn't have to deal with her projectile at all. Even Noob Saibot, who is merely mid-tier, has moves that are still particularly hard on Sonya as she has to just contend with a wall of projectiles and then up close he has a very solid special to swat her away. I'm not so sure about Skarlett, Reptile or Ermac beating her, but I don't have much experience with them so I can't really comment.
The point of this post is to say that even though I would generally agree that there are very few types of zoning that are viable at the highest levels, there are still some characters who are quite susceptible to the basic zoning that isn't so effective against the higher tiered characters, and Sonya is one of them. As long as that is true, and she loses those matchups, there's no way you can really effectively say that she is number 1 or 2 or whatever. This reminds me of how Johnny Cage is feared because of inexperience, and Sonya is the same way. Now granted, Sonya is a much better character than Cage, but there's still an aura of mystery for a few scenes that makes her appear much much better than she is...which again, is not to say she's bad (Top 10 is not bad lol) but she's not the greatest character in the game. Not by a longshot, logic kind of defeats that idea after so long.
