Is mass farming vegetables as inhumane as mass-farming cows, pigs, chickens etc? probably not.
But mass farming insects may not be anymore inhumane than the life wild insects are already accustomed to (living in tight, dark spaces).
From a sustainability standpoint, there's no question that getting your protein from insects is better for the environment than cows/pigs/chickens.
But some people are vegetarian just because they're generally grossed out by eating bloody flesh...so just from that angle i'd say insects are not vegetarian.