Not able to hold the trigger/destroy key to continuously destroy crops/grass

Whist able to hold down the right trigger in order to continuously break wood/stone or indeed any type of item or block, crops and grass seem to be the only exceptions to this ability, and instead have to be broken one at a time by repeatedly pressing the trigger. It cannot simply be held down in order to break multiple blocks. I have discovered a work around solution however, by first aiming at a different block, for example an adjacent grass block, pressing the trigger, and then moving onto the crops or grass while continuing to keep the trigger held. Is this a bug, or intentional behaviour? I feel it would be an odd inclusion if it was indeed the latter. Thanks for your time, and for constantly improving the gameplay in Minecraft.