The moment you stop blaming others on your faults is the moment you'll start improving.
I started improving after I took a free 10-day meditation course (the Goenka one), four years ago. At the course, I gained the ability to notice changes in my emotions and mental state. Suddenly, I could see when my mind switches to a judgmental attitude. I began intentionally trying to prevent the switch. I also intentionally restrain myself if I do switch into that mode. Changing mental habits is difficult and worthwhile. I have improved a lot in this area in 4 years.
Two years ago, I realized that my parents taught me to be a judgmental jerk. Since that time, I have considerably reduced the bad mental habit. People close to me confirm this. Therefore, my experience contradicts your statement.
Fixing those (forming judgements when they serve no purpose; feeling excessive ill emotions over judgements) is about half of the self-improvement part of stoicism, as in "think the right way, and act the right way". It's most of the "think the right way" half.