Since when has no 100% counters mattered? There are a variety of pokemon in ou that don't have an 100% counter.

ok name them.

how wana battle if you pm me

salamence, tyranitar, heatran, metagross, jirachi, azelf, gengar, lucario, infernape, dragonite.

salamence is uber. ttar is very versatile but all the sets can be countered. heatran gets walled by blissey. Metagross gets walled by swampert, rotom-a, skarm, etc.

id go on but im too lazy.

I was under the impression that all of latias's sets were countable. On a side note metagross can take on swampert and skarm, just with different sets. He's in the same boat as tyranitar.
Edit:I would like to point out that I agree with her being uber though