The ethical solution to garden pests

Snails and slugs: use a shovel to scoop them out onto an area you don’t mind being a tiny bit contaminated by snail/slug guts. Then, use the shovel to hit it (hard). Check if it still moves. If it does move, then try hitting it again with the shovel. If it doesn’t move, it’s likely dead. Then, if you want extra fertilizer, and if you’re not disgusted, scoop up the remains and bury them into the soil of a plant. This is ethical, because you’re minimizing the amount of suffering that the snail/slug needs to suffer during death.

Bugs: leave them be… just let their short lives kill them, or put natural predators that eat them in your garden.