First of all, I think it has something to do with China writing Chinese characters from left to right. I've seen left-handed handwriting, and I can tell at a glance that it's written by my left hand. Like you, it is easy to see that it was written by my left hand. The strokes are a bit stiff and unnatural.
Secondly, this is a person's habit. Habits are hard to change, especially when you are young. There are also left-handed ones that look good. The key is to practice by yourself, and there are many people who can't write well with their right hands.