They can't ban a single moveset... it's either the whole Pokemon or the whole Pokemon.. same case goes for Deoxys-E. If it was only the offensive sets, no doubt he is OU, but the defensive one is that made us test it in the OU tier.
Same with Chomp and it's Yache. Ban hax itens to decrease luck is completely different to ban these berries because "they are too good". The opposite, these berries make the game even more doubtful, you are risking a possible power up item to resist an occasional move. But since the only way to deal with Chomp is Ice moves - no, no Dragon moves, nothing carries a Dragon move and it's faster than Chomp + can OHKO. (Also, it is bulkier than Swampert) Garchomp can simply abuse Yache with ease ... not to say Sandstorm makes everything harder.
About the videos posted, the last one is such a joke. Not a single of the examples were countering, yet, revenge killing. The second, Glaceon does resist it's Outrage, but what about Stealth Rock? It's not even an 80% counter (because of Sand Veil), but it seems like a 30% one... still not even close to be usable.