In my opinion, it is almost impossible for a ball carrier to deliver a good stiff arm to the face (I'm saying "to the face" mind you) WITHOUT grabbing or hooking a piece of the facemask in some way, shape or form. And more times than not, the ball carrier is NOT penalized for just that - certainly (in my view) much less than a defender tackling up around the head and inadvertently grabbing the mask.
So that right there is the double standard that I think is being talked about here. I didn't take Izzy as talking about the specifics of the rules, I saw him as railing against the "double standard of the stiff arm" and it's application. In other words, the double standard of damn poor officiating...............and it's not just a one off here and there..............I believe it is systemic with regards to this situatuon.
I defy anyone to say that in Izzy's first photo, the defender's helmet isn't coming off due to the pressure applied to the bottom of the facemask. In my way of looking at things, that facemask is being yanked up and backwards - yes, admittedly not in the normal fashion of coming from behind and yanking up and backwards - but up and backwards, none-the-less. That should be a penalty, by rule, and by fairness, and the fact is, it is most often NOT called as such. A "double standard" due to misinterpretation and misapplication of the rules.
And this coming from a once-upon-a-time ball carrier.