The thing is, baton pass as a move is not broken, not like Swagger which could only be used to turn the game into a coin flip. It's the synergy between multiple mons. If we can get the complex ban we've gotten already, at least in theory there's no reason we can't just change it to better balance the metagame. No need to just flip the table and go overboard.
The OU pokemon that learn Haze and can spare both a moveslot and a turn for it are Quagsire and possibly Vaporeon. Vaporeon isn't that great (it's not even ranked in either viability thread. To put that into perspective, even Moltres is ranked at D), leaving only Quagsire. In UU, the only pokemon with room/time for Haze are Milotic and possibly Crobat, both of which also do very poorly in OU (both are unranked like Vaporeon). There is also Politoed, but he's really a hindrance if you're not running a rain team.
So we're left with Haze Quagsire.
As for Perish Song, in OU you've got Azumarill, Gengar, and Smeargle. Smeargle might be able to run it, but it's frail, and the other two have neither the moveslot nor the time. In UU, the only viable user of Perish Song is Celebi, which again is pretty meh in OU.
So it's not like Gen 4-5 where Roar/Whirlwind was an adequate answer and there were lots of really viable users of those moves. Basically, you're asking everyone to run one pokemon (Haze Quag) just to counter this playstyle. That doesn't sound like a balanced metagame, which is what Smogon goes for instead of just saying "lol bring a counter" about everything. That logic could be applied to lots of things that are currently banned, for example, why ban Kyogre when you could just bring Specially Defensive Assault Vest Lanturn with Thunder? I know that's a huge exaggeration, but I only use it to make the point that it's not about whether there are "counters," it's about how effective the counters are, how much having to use the counters limits teambuilding, and how viable the counters are in the general metagame.