Whether we choose to think about it or not, humans in their daily lives directly cause immense suffering to the little creatures. Leaving them half crushed, spraying poison, drowning. Have you ever observed these events closely, and possibly worsening the situation for the insect: tear off a leg, peel a wing?
When I was a kid I took a magnifying glass outside a few times and set the ants/beetles on fire along with grass and wood chips.