Do you need to play like max stealth to avoid this idiocy?
High Stealth helps a lot. But there are other options.
There are certain armour types that can make dealing with Locusts easy as you can make yourself immune to their damage types and/or the damage types you can use to deal with them en masse. Snipers are a very good way of dealing with Locust Nests as you can shoot them while they are in the Fog of War, which means you can take them down while half the Locusts are still inside without engaging in combat.
Crabs are much more easily dealt with either by using high damage singular attacks like Impale, Snipe or Aimed Shot, or Energy Weapons, Acid and/or Toxic Gas. Raw armour-piercing rounds are actually quite bad against those.