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?
It has already likely been done once and documented. I disagree with this, but even if someone were to agree with it, it’s already on the internet to be watched if for scientific reasons (hopefully not sadistic) so that it doesn’t need to be done again.
The counter to this is that humans are important, so if an alien species were to come here, all the aliens should torture a human at least once because we are important to understand.
This is a very similar scenario, and everyone would probably agree that if said aliens were to torture a human, that it’s absolutely terrible. We are now the insects in this scenario.