Yes, there is a difference, but I don't think this distinction is what we are dealing with here. The animal deaths that occur when harvesting plant crops aren't accidental, instead they are the direct result of the sort of equipment that is used. If, for example, wheat results in the same amount of animal deaths per calorie as dairy how exactly is one cruel and the other "cruelty-free"? Cows are culled in dairy production for much the same reason animals are killed when harvesting plant crops, namely, methods that seek to maximize profit. As mentioned, in the case of grain fed cattle dairy will always result in more animal deaths but I've yet to hear a convincing case that this is the case for pastured dairy.