A lot of things can counter FEAR.
Abomasnow or Tyranitar or Hippowdon
Ability: Snow Warning/Sand Stream
The rest doesn't even matter, the point is that the Hail/Sandstorm will break their Sturdy/Focus Sash and so render the strategy useless. Abomasnow is probably better because one of the FEAR users (I think, from memory) is Aron, which is immune to Sandstorm damage.
Anything with Toxic or Will-o-Wisp works for the same reason - it breaks the Focus Sash. These are extremely common moves competitively, so even most teams that aren't specifically preparing themselves to deal with FEAR will still have them.
Ghost types are immune to Quick Attack, and so can also stop most of the FEAR Pokemon (e.g. Rattata).
Skill Link allows Pokemon like Mega Heracross, Cloyster, and Cinccino to ignore Focus Sashes and Sturdy by having moves like Pin Missile and Rock Blast hitting 5 times.
Priority will also stop this strategy (unless the FEAR user has Extreme Speed).
There are a lot of options to deal with FEAR, and most of them are very common competitively, which is why FEAR is not the best strategy to use.