And how many of those Culise are used for their flying attacks?
Most of the time they are simply used for their immunities. Heck one of the Charizards lose their flying.
All I'm meant to say originally is that there is no evidence that "no one likes flying types," considering that 13 of the 48 OU Pokemon are exactly that. I went on to countering Breloom with fliers, and that's why I separated the two lists and explicitly specified Charizard Y. The first list does frequently run flying attacks (as do Skarmory and Togekiss); for the second list, it's typically enough that the Pokemon can shrug off most of what Breloom can throw at it, thanks to their flying type, and hit hard with neutral attacks. Mandibuzz, for instance, is almost a perfect counter - Overcoat blocks Spore, Foul Play turns Swords Dance against it, and it'll take 3-4 turns for Breloom to do enough damage to knock out Mandibuzz. Gliscor worries only about Technician Bullet Seed, and that only if it's using a Toxic-stall set (which, to be fair, is the main set). Skarmory doesn't even care about that. Dragonite trivially gets the OHKO without even a single super-effective move or any boosts, and even outspeeds Breloom as long as it's using Jolly; Jolly Gyarados has a good chance at the same with a single Dragon Dance and the non-STAB Ice Fang (and Adamant guarantees it). The others, however, need to worry about Rock Tomb, and Spore is a threat to everything except Mandibuzz unless you run a format with Sleep Clause and sponge it off on another Pokemon first.
Basically, Breloom's sets are unpredictable, which means that you need to figure out your counter based on what it runs, and that takes time in which it is setting up and getting ready to sweep. There are more reasons why Breloom is dangerous than just "no one likes flying types." Umiman pretty much summed it up, especially outside of formats that use Sleep Clause. It's not overpowered, but it's not a matter of no one using fliers.