Hey! Welcome to Kunming.
Discrimination and bias of of any kinds exist in both China and Japan and anywhere in the world,too.But still there are more friendly and peace loving people out there.Despite what you have found from Sankei,Kunming is definitely safe for Japanese.
My teacher back in college,Miss Suzuki,who is from Fujisawa,Kanagawa Prefecture,is probably the most famous social activist in Kunming.She has lots of students and has just started a speech contest among universities in Kunming.She herself is just the symbol of friendship between Kunming and Japan.
Wish good luck.