Firstly, it's nowhere near 8 yards. It's 2 or 3 maximum, and no ones overly bothered where a free-kick is taken in that area of the pitch (within reason of course) because it's not affecting play.
Secondly, the ref probably doesn't see the incident in full because he's moving away from the area, expecting a quick free kick to be taken. The likelihood is that one of the remaining 3 officials has seen it and advised him what's happened and offered their opinion on the sanction.
At the end of the day, Rice has delayed the restart, the Brighton player doesn't actually appear to make a lot of contact with him. Rice's only intentions are to delay the restart to give Arsenal an advantage to get back into position and therefore rightly receives a C4 caution
Really don't think anyone can have any arguments with that whatsoever because its not an incorrect decision. The media have made it out to be a lot more controversial than it actually is.