I agree with you in some points.
I agree how you feel devastated.
Same thought also come to my mind.
Usually most of website where provide 'Language Exchange' are commercial.
They connect professional teacher/member and students.
This site, too.
Also, English is one of the most preffered word, many people want to improve their skills.
But correcting 'perfect' is very difficult even who using English as a mother-tongue.
I found myself I cannot correcting Korean in grammer ways, even I am Korean, and I have a very good score in Korean in my school days.
Such as you, you don't need any corrections in grammer, in my view.
Also you cannot be friends with your english teacher.
It is hard to correting, and they want to get job.
Nornal english user could not correcting your writing easily.
But you still want to improve your skills, right?
What you need is, how to express your opinion more persuaded ways.
For that, you are better to take a class 'how to write" or running a personal blog.
Are you majoring Sociology?
I am majoring Sociology.... so I want to talk dare.
I thought you may think more critically when you want to call your writing as a "sociological topic"
Language Exchange is a one of commercial decoy for selling sevice "class".
Learning language is also reflect power of the country.
English is most powerful language in the word.
If you good at English, you have more chance to success.
People who native in English have no motivate to learn other language.
(It is bitter truth...)
But, English native and not native has a common.
Even a English native, have to learn HOW TO WRITE.
You has a great English skills.
What you need is improve your writing skills and critical thinking (or thinking more sociological)
Thank you.
Have a nice day!
P.s. My comment is rather longer than other, I posted here for easy reading.