The reason GR15 has been added and why breaching this rule will result in a ban is because ponies used to be posted everywhere. That is in a similar fashion to the frogs, except frogs have been posted in every single board for a long time without a single repercussion; despite being hated by most, just like ponies. The only ones who don't mind it are frogposters themselves. So why aren't the frogs getting the same treatment as ponies did?
>pepe is 4chan's mascot
No it is not. Yotsuba is. Allow me to put in a perspective (you)'d understand: Country is mainly made up of natives. All is swell. Migrants come in. They keep coming in. That is until they're the majority. Migrants claim they're the natives. With some time, it will believed. See North Africa, or Vietnam.
Pepe is cancer, and has been outside of 4chan a long time ago. I say, we remedy to it in the most radical way possible.