I only saw it once and thought exactly the same. Even if that was a foul, it was a ****ing harsh booking.
But a first booking is often soft. The key is how you respond, and he responded with a daft tackle that you shouldn't make even if you're not on a yellow.
Poor lad has developed a reputation for having a 'discipline problem' from an outrageous red card, a sloppy challenge at West Ham and then this.
Didn't he also get booked from the bench before even making his debut?Welcome to Arsenal.....