Wait what? Why do they take issue with you running mana rocks of all things?
Aside from mentioning Yosei, my suggestions were all for how to make a Hokori deck better. Just saying.
If you are purely going down the spite route then there are a few other options out there too:
-Zo-Zu the Punisher land hate: Definitely teaches people to not rely on land, and a bit more consistent then a Hokori deck. tappedout.net/mtg-decks/zo-zu-land-hate-edh/
-Maga, Traitor to Mortals/Oona Queen of the Fey/Ambassador Laquatus: Can all outright kill people if they have the mana, so just focus on ramping really really hard into infinite mana combos before they even get the chance to do all that much.
-Maraxus of Keld voltron: One of my pet projects, my plan is to mostly run mana rocks, token production, and board wipes. Basically you just ramp faster than anyone else at the table and swing across with a huge Maraxus. When other people start to get a reasonable board then you just wipe it, and you ramp so quickly that you are always going to reestablish faster than anyone else at the table. Honestly your meta seems like the perfect place for a deck like that because of how slow everyone else would be without mana rocks.
-Numot, the Devastator: LAND. HATE.
-Vorinclex, Voice of Hunger: Mana excel and land hosing at the same time. You don't even need to run mana rocks in this one, so it would be a more subtle prompt, but it definitely has a better diversity of potential win cons than Hokori.
-Zedruu the Greathearted: A bit of a weird suggestion but hear me out, kill them with kindness. Force them to see how awesome mana rocks are by forcibly giving them to them. If they actually get the chance to use them then it wont take long for them to learn to love them.
-[INSERT MARDU COMMANDER HERE]: RWB has the best land hate in the game, so if you just build around land hate first and foremost the commander can be a bit of an afterthought with this color identity.