I've found you some back up. After three pages of posts complaining about Xhaka's stupidity, one Arsenal fan on an Arsenal forum asks whether it is a penalty because the contact wasn't very hard...
These things even themselves out over the season we are told. So, following Kyle Walker being sent off for doing nothing next week, we'll be getting half a dozen dodgy penalties given in our favour. Could also be an interesting game at Wolves where Mo Salah is somehow going to get five or more...