Earlier quoted context omitted.
What do you mean by "(here)"?
I think he is referring to your text at the top of this post, as it is not proper English. As another data point, I would disregard your application immediately upon being asked to 'Sing In' and 'Sing Up', which is clearly a rookie typo/shows a lack of attention to detail. https://i.imgur.com/Pwwmsda.png Regardless of what anyone says, keep going at it and get better every day.
You would disregard a non-native PROGRAMMER because on the front page of his side-project says"Sing" instead of "Sing". That's extremely harsh. I might even consider it stupid.
I think he is applying as a developer, not as an English teacher.
ps. I've read a lot of comments like this one, in various threads here and on reddit. I really wonder if the people who make those remarks are equally austere with themselves.