I don't think this is true because the assumption of Arsenal being elite probably isn't true anymore.
In all seriousness, I just don't see how a grab of the throat like that isn't violent conduct. If Martin Atkinson and his crew said they saw it and aren't taking further action, that's not right. If they missed it and VAR didn't come back to say, "We have to sanction Guendouzi for violent conduct", then VAR is wrong.
In any case, PGMOL has to account for this. The idea that a clear choking action (even if it's not actually choking the other guy) is not sanctioned needs to be explained.
EDIT -
@LothianRef just beat me to it . . .