I didn't say they're the best weapon, and i'm not sure how being used in group fights makes a weapon good or bad in general. Lots of people use hammers in group fights but don't in duels, does that mean clubs are bad weapons because they're only "viable" in one type of combat? People will use the right tool for the job, and if poleaxes fit someones needs for how they want to play or what they want to do, they can use them.If they are so good, why does nobody uses them outside of 1v1 tournaments?
Sword is still way better with more attack directions, less stam drains and less handle hits. Spears are way better in group fights where you wont get free parrys or space to do fancy mix ups with spins.
They have the same number of attack directions as a sword, all directions will deal good damage on a poleaxe, and they are longer and hit harder than swords do. If those are things a player is personally willing to sacrifice stamina drain and handle hits for compared to a sword then poleaxes might be a good choice for them.
My main point is that they aren't as bad as some people are saying they are. They do have benefits and uses, and can be used very effectively in the right hands.
Another point worth making, is that quite often people complain the most about things they want to use, or are already using but want to be better. I would place a reasonable bet that a lot of people who are saying poleaxes suck actually do use them, and simply want them to be better so their weapon of choice is better. Not that this really affects the discussion, but it's worth noting.