Don't worry, that guy is clearly just an idiot. His account is full of games where he just insults his opponents in German, French, and English, whether he beats them or they beat him. Like below, which is actually one of his calmer games (in terms of number of insults).

_________________
We don't know who we are; we don't know where we are.
Each of us woke up one moment and here we were in the darkness.
We're nameless things with no memory; no knowledge of what went before,
No understanding of what is now, no knowledge of what will be.

Bizarre to be insolent to someone who gave you an undo...