Chansey can't phaze..., and max SpD/HP Skarm is still 2/3HKOed by Hydro Pump and Surf respectively.Well, hydro pump only has 80 accuracy, so they're banking on multiple things. Something that's a mixed wall (Eviolite chansey, or a SpD specced Skarmory) should be able to handle both in at least some regard.
Keep in mind that people are only going to use Bibarel (if they're being serious) if they're already using the better abusers, Octillery and Glalie, both of which eat Gliscor and Haxorus alive. Jellicent can't damage the two much, and is vulnerable to Toxic, especially since Glalie outspeeds.Furthermore, something like Gliscor (Again, with the Hydro Pump weakness, but bibarel's SpA is only 55) can taunt first, and Haxorus resists water but has a weakness to ice. If I'm worried about ice I can bring a Jellicent instead.
Note that if a Moody abuser is on the losing side(by getting the wrong boosts, being perfectly walled), it can switch out and try again later. If a Moody counter is on the losing side(they get the right boosts, or the counter has been worn down), the team gets swept. This alone make it biased far towards the Moody abuser's side:The end result of this line of theory is that it's possible for a pokemon with Inconsistent to, assuming it has the right moves at the right time and gets the right stat-ups, beat any other single pokemon one-on one. Maybe.
That just doesn't sound powerful enough for me.
If a Moody abuser has 6 chances in a match (lead + come in after every teammate's KO), if it gets wrong boosts 5 out of the 6 times, it can still sweep if it gets the right boost on the 6th.
If a Moody counter can successfully counter 5 out of the 6 times, you still lose on the 1 time that your Moody counter failed.