When the gamerule mobGriefing is set to "false", villagers fail to accept carrots, potatoes, wheat, and wheat seeds into inventory. Villagers fail to navigate towards grown crops, destroy said crops, and then replant said crops. Setting gamerule mobGriefing to "true", villagers successfully perform all actions listed above.
Linked issues
Comments 4
Villagers are non players, yes, but they are intended to be MORE than the standard mob as they are the only mob with any significant player interaction. Although the mobGreifing rule is applied to any alterations, it is called mobGREIFING, not mobAlterations. Greifing is a destructive alteration with a negative outcome, whereas the villagers farming is a constructive ( or regenerative more specifically) alteration with a positive outcome.
This is not "resolved". mobGriefing was and is intended to prevent Endermen moving blocks, Creepers blowing up blocks, and Wither/Enderdragon removing blocks. The villagers are doing none of these but are instead removing crops, which are meant to be harvested in the first place. Simply not letting them do what they've been coded to do to survive is unacceptable and this needs to be changed. Their new behavior makes this and trading with them the only way for them to survive, and a non-hostile mob surviving is in no way griefing. Even then, the promptness in which this issue was set to "resolved" is very disappointing, especially since no Mojang employee has even looked at this and said it is truly intended behavior.
It's already been posted anyway
See MC-55218
Why don't you post the suggestion on reddit. Maybe Grum could make a new gamerule or something to allow Villagers to farm.
Actually, it's been discussed
http://www.reddit.com/r/minecraftsuggestions/comments/1y8kip/new_gamerules_for_mobgriefing/
http://www.reddit.com/r/Minecraft/comments/1xguvz/psa_gamerule_mobgriefing_affects_villager_wheat/
Continue your discussion there though.
Works as intended. The gamerule does not allow non players to alter the world. Villagers are non players.