This is because a counter doesn't need to be able to take more than 2 hits as long as it can hit back and beat Ho-oh. According to some of the arguments I've seen against me so far, even Bulky Waters hate to get burned now - what doesn't hate to get burned? Everything hates a 12% health loss at the end of every turn, but these things aren't completely ruined by it. The main reason I keep mentioning counters is because counters are effectively how things end up fainting - what else faints a pokémon you don't have a counter for aside from residual damage (which is a big problem for Ho-oh already)? I don't understand what you mean by that comment.You have listed very few, if any, counters not 2HKO'd by Thunderbolt / UnSTABed CB moves, or screwed over by being Burnt. This is COMPLETELY IGNORING that your argument for OU is based on the fals premise that things are made Uber if they have no counters, which is just one of the reasons people voted Chomp banned. Counters aren't even good responses anyway.
As far as things that can actually take hits from a mixed Ho-oh, probably the best "counters" of the lot... [alphabetical and grouped with tier] Ho-oh doesn't have much for Flygon and it can hit back at it with Stone Edge, already outspeeding it the process; Hariyama and its Thick Fat I have mentioned; Lickilicky takes barely anything though most physical sets hate a burn, it still walls it regardless (CB SF would hit hard, but something like a Curser could boost up against Mixed sets and Rest off burns); Ludicolo gets more back from Leech Seed than it loses from Burn and has Rain Dance to weaken Sacred Fire and boost Surf, as well as putting it in danger from Swift Swimmers; Porygon2 is bulky enough to take its hits and can Pressure stall thanks to Trace; Regirock walls them all easy and would do well to be running Resttalk anyway; Rhyperior I've already done; Tauros can Intimidate and hit back hard with Stone Edge, though it won't be coming in on Sacred Fire; Uxie basically walls it and can set up SR, use Yawn, use Toxic, whatever; Umbreon I have already covered... Onto OU: [Blissey can wall all special sets aside from Calm Minder if it lacks Toxic], Cresselia walls Ho-oh without any trouble; Deoxys-S and its Cosmic Wall set can take Ho-oh on, and a Taunt / Reflect / Light Screen / Recover variant can wall it (even with Burn) and pave the way for lots of new counters to come in with beefed up defences and a Taunted foe; Dragonite can take hits and Lum Berry protects it from that lucky Sacred Fire burn; Kingdra wins and I don't need to explain that; Salamence is in the same boat as Dragonite though only BulkyMence could take Ancientpowers and Lum Berry is a rare site on it; Thick Fat Snorlax beats them all easily; Swampert I have already covered; Ho-oh with Toxic walls just about every other Ho-oh despite not being too good itself, and Zapdos with Thunder Wave just needs one turn of paralysis to beat it with Thunderbolt, though it's risky because Burn could be annoying.
That's all I got on those two tiers, excluding Bulky Waters as they hate T-bolt. There are tons more "riskier" counters that can switch in on certain moves and OHKO back, but yes.
@Skyshroud: How am I not listening to reason?
I'm not the only person who is arguing for Ho-oh to be tested, it's not Smogon vs. Jetx.